Computer software malfunctions. Troubleshooting software and hardware of a personal computer

02.07.2020 Windows 10

Primary diagnosis of a computer malfunction

Primary diagnostics can be done using BIOS signals that are reproduced when the computer starts. But for this you need to know the breakdown coding tables. Each BIOS developer (AMI, AWARD, PHOENICS) uses its own code for the type of malfunction. One short beep means for everyone that the initial test (POST) has passed, no errors were found. Still the absence of any signals means that the system does not start when power is applied and the power-on signal is applied. But then it's different for everyone. Read about computer troubleshooting
Sometimes you can tell a hardware problem from a software problem by seeing how the computer behaves after a power outage. Unlike software reset.
Many computer malfunctions can be set to fatal in Windows. But for this you need to make Windows itself work. For example, fixing the death screen error.

Computer hardware malfunctions, symptoms

Processor failure

What are the signs of a processor malfunction:

computer restarts cyclically
motherboard won't start
no boot from hard drive
won't install and also won't boot Windows
sometimes programs work with errors.
the processor is very hot, as well as the processor power parts on the motherboard.

If the processor has a built-in memory controller, then memory errors may be due to a faulty processor. A faulty Intel processor is extremely rare. But burnt AMD processors are a regular occurrence.

The processor can burn out due to improper assembly if the pins of the board or processor socket are bent. Especially with a short circuit. In this case, the processor is replaced with a new one. It is difficult and risky to determine a processor malfunction at home. After all, it is dangerous to check the malfunction of the processor on your board. Because a burnt processor is able to “burn” the motherboard.

Computer memory not working

Signs of bad memory are as follows. The computer does not boot, intermittent crashes occur, accompanied by a blue screen of death in Windows and applications. reliably diagnosed by special reliable tests. Programs with low validity work quickly, but often do not detect a malfunction.

Tests should be carried out on a motherboard that has a good memory controller. If the controller is in the processor, you need to test it on a known good processor. A memory test with a low confidence program can only confuse you and take extra time. A good memtest program.

Faulty memory should be replaced, it is pointless to repair.

Computer motherboard malfunctions

If the computer motherboard does not work, then the symptoms are as follows:

the computer does not turn on at all, or turns on but does not boot;
the computer's USB, sound card, and USB keyboard and mouse do not work;
processor is cold
Windows does not load or install, the processor overheats.

Troubleshooting: replacement, repair.

Hard drive problems

Symptoms of a failing hard drive:

the disk does not spin up, is not detected in the BIOS of the motherboard;
Windows does not boot, the computer restarts cyclically, freezes, slows down;
regular errors and crashes of programs.

Hard drives are worth repairing if the damage is minor or if they contain valuable information.

A broken SATA cable and poor contact can also be the cause of a bad or unstable hard drive. You can diagnose poor cable quality by the UltraDMA CRC Errors parameter in S.M.A.R.T.
More about .
Troubleshooting: replacement, repair.

Another frequently asked question related to the fact that Windows does not see an external hard drive that is connected via USB. First you need to check if the disk itself is spinning up. If there is complete silence or the disk attempts to spin up (does not gain momentum), then the disk does not start. Therefore, Windows does not see the HDD. The reasons may be the following:

The disk does not have enough power to work (insert the second end of the splitter into USB);
Bad cable (the performance of external hard drives is highly dependent on the quality of the cable);
disk controller in low quality box;
You are connecting incorrectly - for example, through the front USB connectors of the computer, but you need to connect to the motherboard from the back.

Here are the main reasons why an external drive does not work on a computer.

Video card failure

Video card symptoms:

garbage, as well as artifacts on the monitor screen, often even before Windows loads;
the computer does not boot - there is no characteristic boot sound signal;
3D games crash;
the video card driver crashes and is not installed, games do not work, the 3DMARK test crashes.

A typical cause of video adapter failure is overheating. The critical temperature for a video card chip is about 105º C. To avoid overheating, do not bring the card to such a temperature, do cleaning in a timely manner. The problem is being checked on another computer.

Computer power supply failure

The fact that the computer turns on and the fans are spinning does not mean that the computer's power supply is working well. It is possible that it is the power supply that is causing the computer to stop working. The power supply has many parameters that it must provide:

computer supply voltage stable under load + -12V, + -5V;
limited rectified voltage ripple and high-frequency noise;
supply the required current to the load.

The computer may not work or be unstable if:

at least one voltage is reduced;
has ripples more than allowed.

Over time, any power supply loses power due to aging capacitors. But computer failures can occur due to insufficient PSU power.

Symptoms when you need to check the computer's power supply:

the computer does not turn on with the button (power is not supplied to the board, as well as fans);
no boot from hard drive;
the computer restarts cyclically;
when turned on, an error is diagnosed;

Power supplies have practically ceased to be repaired, because a standard power supply costs the same as a repair. Repair only expensive blocks.

Computer overheating

Often, computer breakdowns occur due to overheating associated with the dustiness of the system unit. Because dust is a good thermal insulator that prevents heat dissipation. In the photo, the video card burned out, because the computer was not cleaned of dust at all.

Overheating of the processor leads to the fact that the computer starts to slow down, slow down. The overheating of the processor itself can occur due to:

malfunction of the cooler mounting, which leads to an air gap and a decrease in heat dissipation;
wear and contamination of the fan bearing, which hums or vibrates at the same time;
contamination of the fan radiator;
as well as incorrect BIOS settings.

Computer component incompatibility

Incompatibility of components is a common reason for the inoperability of serviceable devices. Most often, incompatibility occurs in a combination of Intel-AMD components. For example, they replaced the Nvidia video card with a new card from AMD and the computer stopped starting.

But the incompatibility of computer parts is difficult to diagnose.

Computer software malfunctions

Half of computer failures are due to software problems. This includes file system errors during power failures while writing to disk. The reason may also be errors in the operating system, its applications, drivers, the effects of viruses.

Possible causes of virus infection:

visiting phishing sites, opening infected emails, and downloading infected programs;
most likely, the computer has poor anti-virus protection.

If you need professional diagnostics or computer repair, questions about prices, through the contact form. In the vast majority of cases, the cause of the breakdown cannot be determined without diagnostics.

A computer, like any other technical device, can fail sooner or later. There may be problems with the operating system or with the hardware. If problems with the operating system can appear within a short time after installation, then the components, as a rule, have a long resource: you are more likely to change your PC to a newer one than something will break. Of course, this is only possible with proper operation of the PC.

Prices for basic services:

Type of work	Cost, rub.
Home visit within the Ring Road	is free*
Computer diagnostics (software)	is free*
	350
	250
	500
	250 - 350 rubles. per piece
Installing, configuring and uninstalling games and other programs	from 250 rub. per piece
Installing Windows XP/Vista on Apple Computers via Boot Camp	+400 rub. to the cost of installing Windows
200 rub. in 15 min.
Installing Microsoft Office	350
Installation of software packages (Microsoft Office, Adobe Photoshop, AutoCAD, 1C)	600
Installing codecs for watching videos	250
Installing the service pack (Service Pack)	250
Installing Windows XP, Vista, 7	500

Software malfunctions

The main software failures include the following:

Errors in the drivers
Crashes in the operating system
BIOS errors

Driver errors. For the operation of any PC device, both internal and external, a special program is required - a driver. As a rule, drivers are installed automatically on many devices. When manually installing them, you should select the exact driver version that is required by this device. Otherwise, either the device will not work correctly, or it will not work at all, or there will be conflicts with the OS. By choosing the latest driver version, you are guaranteed to get all the features of the installed device. This is especially true for new high-performance graphics cards.

Failures in the operating system. OS of the Windows family is a well-oiled mechanism. As a rule, rash user actions or exposure to malicious programs lead to failures in its operation. Incorrect installation of applications, drivers, their incorrect removal, neglect of maintenance of logical drives - these are the most common causes of OS failures.

BIOS errors. The basic input/output system is an important part of your PC. It is the BIOS that determines the devices when Windows starts, the priority of devices for loading the OS, the frequency of the system bus, video card, voltage, and much more, without which the computer simply will not turn on. Errors in the BIOS can occur after the operation of viruses, power surges, battery failure, which ensures its non-volatility.

Characteristic signs of software malfunctions

Computer freezing at work

Error messages appearing during OS boot (blue screen)

Game apps won't launch

Various manifestations of virus programs

It is impossible to unequivocally judge software failures only by the listed signs. Some "symptoms" may appear as a result of malfunctions of certain components.

Hardware failures

A long service life is typical for all computer components. However, a user who does not monitor his PC runs the risk of replacing the power supply, video card or, for example, the processor very quickly. Almost all devices in the system unit generate a large amount of heat. Banal dust, if not removed periodically, can cause a short circuit, overheating of high-performance video cards or even advanced motherboards. Installed coolers simply will not rotate when clogged with dust. Efficient ventilation inside the system unit is also important. Therefore, it is not recommended to install it near heating appliances or close openings in it: the manufacturer has thought out the issue of cooling for you.

The issue of PC power supply is of great importance. A working power supply provides voltages in a clearly defined range for each device. With voltage fluctuations in the network, the PSU cannot always cope with the surge. As a result, either a burned-out PSU, or a more serious problem. Therefore, the use of an uninterruptible power supply (UPS) is so important, which will not only protect your PC from damage, but also allow you to finish work correctly after a sudden power outage, which is sometimes simply necessary.

Very often, overclockers themselves provoke breakdowns. In pursuit of increased performance, they change the frequency and voltage settings in the BIOS for various devices. If you have already gone for it, then you should do it very carefully: with a minimum step in the BIOS, increase the required indicators and immediately check the performance of the OS. At the first signs of instability, it is better to return the changed parameters, at least one step back. Otherwise, you run the risk of "burning" the processor, video card or motherboard.

All actions with the computer must be considered. A banal upgrade, carried out without a thorough analysis, can lead to the fact that the computer will not turn on at all. Don't forget about the "maintenance" of your PC. If you think that the skills to work with components are not enough, or you simply do not know how to fix the problem yourself, then it is better to seek help from specialists. This will help to avoid many unforeseen problems.

When Windows hangs, we get very annoyed. Especially if you did not have time to save an important document or edited photo.

And if the computer hangs up with the regularity of the change of day, that is, every day, then I can even imagine how your eye twitches from stress. If in such situations when windows 7, 8 or 10 hangs, you don’t know what to do, then this small guide is designed to fill these gaps and guide you along the right path in order to eliminate the causes of computer freezing once and for all.

With the help of this simple guide, you will be able to diagnose any case of computer failure within a couple of minutes.

1. What is a computer crash?

This article will focus on the unexpected crash of a Windows-based computer and how to identify the problem of freezing.

Computer crashes happen for a variety of reasons. An ordinary PC user can encounter computer freezes more than once during work or entertainment. PC crashes often occur due to the fact that the computer is broken or the operating system is damaged.

Just want to warn inexperienced users. Any freezes or sudden reboots of the computer are not yet a diagnosis that the computer is broken and should, at best, be sent for expensive repairs, and at worst, go to the store for a new computer.

As long as no one does any intentional harm to your PC in the form of physical damage, power surges, you can diagnose the problem of freezes and crashes on your own or by resorting to reading this article.

Computer crash

1.1. PC failure is

The easiest way to explain what a PC crash is is to understand how a computer boots from start to finish. The computer, from the moment the ON button is pressed to the moment the working word is loaded, performs several steps, which in brief are as follows:

Enabling the ON button on the system unit;
The BIOS chip checks which hardware components are connected to the system board and the computer's power supply. If all tests pass, the BIOS accesses the boot sector of the disk that is listed first;
The boot sector usually contains a master boot record (Master Boot Record, MBR), which contains a table of disk partitions, one of which is active;
The MBR determines the active partition and transfers control to the boot record, which is usually located in the first sector of the active partition.

From this step, all hardware errors that may occur due to hardware malfunctions end and software failures of the operating system begin. In this case, if the BIOS diagnoses an error in the operation of a faulty component, then you will see the corresponding error message on the screen.

Next, using the boot record, the boot loader of the operating system is launched;
The boot manager reads the system configuration data and prompts you to select a system to boot if there is more than one;
Next, the operating system boot modules, kernel components and the kernel itself, system services and other components are launched;
Then a process is loaded that manages user logins. In this case, if there is one user on the computer, then the desktop will be loaded automatically. Otherwise, the system will prompt you to select the user for whom you want to download the desktop;
During the user's login to the desktop, all the elements registered there are loaded from autoload.

If we imagine all these steps of loading the operating system as a logical chain, then any PC failure is caused by a break in this chain.

Thus, if a PC crash occurs at one of the steps in the computer boot process, then you can already determine what type of failure: hardware or software.

Of course, PC crashes can also happen if the PC is already running. We will talk about this further.

1.2. PC hardware failure

Unlike a software failure, diagnosing hardware failures is much easier. The chance that a hardware component will fail and you won't know which one is pretty low. As mentioned above, during the boot of the computer, the BIOS immediately diagnoses the non-working component of the computer and tells you about it. But it can be assumed that, for example, a hardware component fails not immediately, but during the operation of the computer, for example, when it heats up or is heavily loaded during games or video conversion.

What PC components can malfunction and go unnoticed?

motherboards- provides interaction between almost all hardware components. All your flash drives, hard drives or solid state drives are connected to the mother mother. A damaged (faulty capacitor, faulty port, short circuit of the microcircuit) motherboard will cause the PC to reboot frequently or not turn on at all. Power surges in the electrical network can burn the motherboard beyond the possibility of recovery. Defective slots such as PCI or RAM slots can also lead to similar problems. But, as a rule, motherboards are rarely the cause of frequent PC crashes.

CPU(CPU) / GPU(Video card) - on most PCs, the reasons for frequent shutdowns can be precisely the central processor or video card. The central processing unit handles most of the computer's tasks increasingly in multitasking mode. The GPU handles the events necessary to display graphics on the monitor screen. Overheating of these two important components is the main problem of their failure. The CPU or graphics card automatically shuts down when it reaches a certain temperature threshold. This mechanism protects them from destruction. But I do not advise you not to pay attention to frequent computer shutdowns due to overheating of the CPU and GPU. Sometimes the cost of these two components is two-thirds of the cost of the entire PC. And if you are not a computer enthusiast and an experienced overclocker, then I advise you to periodically clean your PC from dust and check the operation of coolers on the central processor and video card.

Power Supply- the power supply provides the electrical power necessary to start and operate all other components of the PC. A poor-quality power supply can ruin your computer, especially if the electrical network of your apartment suffers from frequent power surges. Incorrect voltage, power surges, power surges, and the like can cause serious damage to all PC components. In addition, the poor performance of the built-in fan in the power supply can cause it to overheat and fail.

1.3. PC software failure

The three main causes of software failure are: OS corruption, program crash, and driver failure. Of the three, driver failure is the most common. Various drivers connect to, and control, various hardware components.

OS crash- an operating system error occurs as a result of a defect in the operating system. This type of error indicates that system files are corrupted or missing. OS files can become corrupted for two main reasons:

Disk sectors failure;
Required system files are missing.

Disk sector defects occur when a physical hard drive is damaged or worn out. Files cannot be read on a damaged hard drive, which is why OS errors and crashes occur.

On the other hand, the problem may stem from the lack of the necessary system files, which are simply not enough. This sometimes happens due to the presence of viruses, whose tasks include damaging or deleting the system files of the operating system. Therefore, if during a certain task that the user or the operating system encounters, there is a shortage of any important files, then the OS will crash and the computer will be sent, at best, to reboot.

Software failure- if the program cannot perform the operation that the user has given it, then it will crash, but the operating system, as a rule, continues to work properly. And if the program causes the operating system to freeze, then the problem is not in the program at all. In this case, the malfunction should be sought in a more hidden problem. For example, if your computer crashes every time you use the Google Chrome web browser, it could be the result of a RAM failure. If your computer crashes every time you start playing a computer game, then your video card may be under severe stress due to its cooler failure. Therefore, do not rush to sin on a program that you do not want to work correctly for you. Maybe it's not about her at all. Next, we will figure out where to look for the source of the error.

Driver failure- driver failure can be considered one of the special cases of software failure. Drivers act as a layer between the operating system and all computer components, from the mouse to the printer. A crash in the driver, as a rule, causes the operating system to go into a reboot. Respected manufacturers of computer equipment and components often release updates and new versions of drivers themselves if many users experience driver failures. Therefore, if you have problems with one or another driver that comes with the device, I advise you to look at the official website of the manufacturer and make sure that the driver version you have is up to date.

2. Symptoms of PC crashes

Of vital importance are the so-called symptoms of computer failures, which can be noticed by an attentive user. The operating system will not write these symptoms for you in the form of error messages. Typically, these are computer performance indicators that act as information that can be used to troubleshoot PC problems and crashes. Crash symptoms do not indicate specific problems, they just suggest that there are some problems that are causing such crash symptoms. For example:

The sound stutters is a sure sign that your computer is about to start to seriously crash or stop responding and freeze. A stuttering or buzzing sound can be either an audio problem or part of another more serious PC problem.

BSOD(blue screen of death) is a noticeable sign of a PC failure. Simply put, a blue screen error is the most popular operating system reaction when a computer crashes. Moreover, the blue screen of death shows an error on the site, the meaning of which can be found on the Internet, for example,.

Windows 10 BSOD with error code

Screen off. Sometimes the computer continues to work and does not go to restart during a crash. Turning off the screen is often associated with errors in the operation of the video card. This does not mean that the GPU is defective, that the graphics card is not fully inserted into the PCI-Express slot, or that the drivers are not installed correctly, are corrupted, or need to be reinstalled. At the same time, the connecting cables that connect the monitor to the system unit can also give a percentage of the probability of turning off the screen, although it is 0.5% of all cases of problems with the video card.

No PC response. PC freezes are often the first signs of a PC failure. The lack of PC response is the complete lack of mouse movement, the response of keystrokes on the keyboard, the audio playback stop and the image freezing on the screen. There is nothing you can do here, except forcibly turn off the computer and then turn it on again.

3. Practice fixing PC errors

Troubleshooting is best done according to some pattern. It is better not to shelve simple failures and errors in the operation of the PC if possible, but to eliminate them immediately. Difficult problems can be postponed and replaced by other more important matters, especially since it will sometimes take up to several hours to eliminate such problems. In addition, some of the PC problems may occur on a monthly basis, while others appear on a daily basis.

Next, I advise you to go through the steps of each section from the first to the last, to make sure that you act in accordance with the severity of the problem. This is a general procedure for troubleshooting any problem. If the step didn't work, then go to the next step.

3.1 First failure

Just restart your computer. If your computer hangs during a crash and you can't force it to restart, then press and hold your computer's power button for a few seconds until it turns off. Then turn on your computer again. Further, the computer will either work without the previously detected error, or the failure will repeat. If the problem occurs while the computer is booting up to the 4th step from , then with 99% accuracy it can be argued that this is a hardware failure. You will have to open the system unit and:

Check power connection- If the PC component is not receiving power, or is not receiving enough power, it will not work. Make sure the components are properly connected to the power supply. Even if you are not an electrician by profession, it is very easy to deal with the power supply of the components of the system unit. The main rule is that from the power supply, cables should go to the hard drive, DVD or Blue-raw drive, video card, processor socket and the common thickest cable to the motherboard.

Check input cables- Make sure that the input cables from external devices to the system unit are in working order. The variety of peripherals for each computer is individual, but almost every computer has a mouse, keyboard, monitor, speakers. And they all have a wire that is connected to the system unit. The connection of such a wire needs to be checked, perhaps one of them departs or is not plugged in at all.

3.2 The problem recurs

speedfan- download . The utility allows you to immediately after starting to diagnose which component of the system unit is the source of overheating for the computer. Download and install the utility, on the tab Readings the speed indicators of the connected fans of the system unit and the temperature indicators of all PC components are displayed. Deviations from the norm will glow red, which indicates problems with the PC of a particular device: video card, hard drive.

Speedfan - temperature

In addition, on the tab charts you can see temperature graphs, fan speeds and voltage readings of important PC components.

SpeedFan - charts

HWMonitor- download . The utility is even simpler than SpeedFan, It allows you to monitor the voltage and temperature readings of all computer components. If any of the components in your PC exceed 80-90 degrees without heavy load, then this is the first sign that you need to take measures to cool it.

HWMonitor

The main cause of overheating, as a rule, is the running state of the system unit and the mountain of accumulated dust. Clean your PC and take measurements again.

4.1.2. Component Stress Testing

Stress test of the video card (GPU) is the best way to see obvious graphics card problems. Stress testing will put a 100% load on the graphics cards, forcing them to perform at their maximum. Therefore, if your computer shuts down while playing a game, it's a good idea to check the stability of your graphics card.

Furmark or Unigine: Valley good stress tests for the video card. During the test, make sure that your computer does not overheat. If the computer turns off during the test, and the video card is not overclocked, then problems with the video card are obvious. To start fixing the problem, try inserting the video card into the slot again and update or reinstall the video card drivers.

Processor (CPU) stress test tests multitasking (among other things), not graphical abilities. You should run a similar test if any brakes and delays occur when you run several heavy programs at the same time, for example, for editing images and converting videos, rendering a 3D model, and so on.

Prime95 or stress tests, which contain a sufficient number of special tests that can load the processor with a variety of tasks. CPU stress testing, unlike graphics card stress testing, often takes longer. So be prepared to spend up to several hours stress testing the CPU.

Stress test of random access memory (RAM)- detection of RAM errors during stress tests. RAM errors can lead to frequent shutdowns unless the memory stick is replaced with a new one. Windows has a built-in Windows Memory Checker. To use it, in the menu START, type "memory diagnostics" and run Windows Memory Checker.

Windows Memory Checker

The first option will immediately send the computer to restart. Get ready for it. This is necessary so that there is no extraneous data in the RAM during the test that can occupy problem areas of memory. If you want to postpone the RAM test, select the second option.

memtest- the best RAM test, but you will need an external USB drive or CD drive to run it. In addition, you need to change the boot order in the BIOS, putting the media with MemTest first.

Hard disk check. It's no secret that hard drives wear out over time. But even during operation, the file system of the disk may be faulty. Disk drive errors not only lead to frequent PC crashes, but also give great risks of losing important data stored on them.

To scan a drive for errors, use File Explorer to find your drive (for example, the C: drive). Next, right-click on it, select Properties, go to the tab Service and press the button Check.

Running Check Disk

I warn you that the computer may be restarted. If errors are found during the scan, the disk check utility will fix them immediately. If fixing errors on the hard drive is not possible, then get ready to replace the drive soon.

It is better to entrust the storage of important data to services and services on the Internet, and not to hope that your hard drive will not fail. The problem of losing important data always comes unexpectedly, and along with the disk, you can lose the most expensive files.

4.2. Analysis of PC software failures

4.2.1. Operating system troubleshooting. If your computer stops starting or boots up with failures, then the matter is clearly in violation of the integrity of the files of the Windows operating system. In order to repair corrupted files of the Windows operating system, let's turn to the built-in system file checker. The System File Checker command will scan Windows, repair and replace corrupted system files. Open the menu START and type cmd. Right click on the program Command line and from the context menu select Run as administrator. In an elevated command prompt window, type sfc /scannow and press Enter. The command will scan the system partition and repair any corrupted Windows system files.

sfc /scannow

4.2.2. Troubleshooting Operating System Boot. If your computer does not boot at all, then there may be two options for why this happened.

The driver of the hard disk, motherboard (less often other devices) was not updated correctly by you, and after rebooting the system could not boot normally;
There was a software failure of the Windows operating system associated with the installed updates.

So, in order to troubleshoot booting Windows 10, you must have a DVD or USB installation disk with the Windows 10 operating system. After booting into system recovery mode, you have three recovery options. Choose for yourself the most preferable.

Windows 10 System Restore

If an incorrectly updated driver is to blame, then I advise you to boot the computer in safe mode and from there do the following in Device Manager:

Right-click on the device whose driver has been updated. From the context menu, select Properties, and then click the tab Driver. Click the button Roll back driver to revert to the previous version of the driver for the device, or Delete so that you can try to install the driver again on your own.

I advise you to use the Snail Driver utility to install or update drivers automatically, which will allow you to install or update all drivers for all devices in the system in just two clicks.

5. Windows Event Log

Sometimes, only Windows log events will help pinpoint the source of PC errors and crashes. Windows Event Viewer will tell you in detail what is happening with your applications, operating system and computer in general. This is the only source where you can find application crash errors, operating system warnings about malfunctions in various services and components.

Windows event log

I advise you to periodically look into the Event Viewer snap-in to be sure that the computer and operating system are working correctly. You should not try to eliminate all warnings marked with a yellow triangle. But you need to know about their existence in order to understand what this or that warning can turn out to be for a computer. So do not ignore such warnings and try to analyze the source of the error. Perhaps this is just advice from the operating system or software.

The red icon indicates operating system and application errors. If the event table in the Windows log is replete with such entries, then you need to pay attention to errors as soon as possible and deal with them immediately. Inaction can be very costly for you.

Summing up...

The system unit of a computer, like a laptop, consists of many components that work together and make up the concept of "computer". Therefore, if one component fails, then the computer simply will not work normally. Each hardware failure is usually a failure of one of the PC components. The system unit in this regard is more advantageous than a laptop, because it allows even an inexperienced user to find out which device has failed.

A software failure can be diagnosed and eliminated by the same means for both a laptop and a system unit.

If even after reading this guide you still have the question "Why does Windows hang?", Write about it in the comments. I'll try to help you.

Most users work carelessly on the computer and do not think that at some point the computer may turn off and not turn on at all. Yes, and quite often a problem arises - a newly assembled or updated computer does not turn on. Even worse, if the computer suddenly stops working. In this case, the main thing is to correctly identify the breakdown. After all, repairs may not be needed.

Why and why?

To begin with, it is worth understanding the reasons that can cause such a phenomenon. As you know, dust and adverse climatic conditions worsen the condition of PC components. Accordingly, the failure of iron can be caused by oxidation of contacts, dust (and, consequently, static electricity) on microcircuits and connectors, and their overheating. Overheating can also be caused by poor cooling.

Also, all these horrors can also be the result of a power surge, instability of the power supply, as well as improper grounding. The first thing that can be recommended here is to use surge protectors, UPS and computer grounding. But remember - it's better not to ground the computer at all than to ground it incorrectly. First, you need to ground the PC case and the modem with the telephone line separately. You should not ground the case to the heating battery, since your neighbors can ground, for example, a refrigerator, a washing machine or a puncher on the same riser. In this case, this "earth" will already become a phase with a potential difference. It is undesirable to ground several devices to one "ground" at the same time. By the way, therefore, it is not recommended to connect household appliances to the same surge protector with a computer, but it is better to power the monitor, printer and system unit from one surge protector.

A good firework from chips can also be caused by shorting a wire or getting power to the ground contact. Therefore, it is always worth monitoring the quality of cable connections and their condition.

Common Problems

Well, if the trouble happened, then you have to diagnose it. So, let's begin. To begin with, we will give useful statistics in order to know approximately where a dog can be buried.

If the computer is in a state of clinical death, then, first of all, you need to do an autopsy and try to find the characteristic smell of burning and find out where it comes from. If not, then it is worth checking the reliability of the power connection. If the check did not help, then you should turn on the PC and check if the fans of the power supply (PSU), case and processor cooler are spinning (at the same time check the cooler mounting). If they do not spin, and the hard drive does not make a characteristic sound of spinning the spindle, then the power supply has failed. The presence of voltage at its output can be checked with a tester by measuring the voltage at the contacts of the system board in the place where the power wiring harness is connected to the PSU. It is worth connecting a new PSU and checking the integrity of the remaining components. To begin with, they must be visually inspected for the presence of burnt elements.

Despite the fact that a working monitor breaks down quite rarely, it is worth checking whether signals are being sent to it from the video adapter. To do this, use an oscilloscope on pins 10 and 13 (ground and clock, respectively) of the 15-pin D-Sub connector of the video adapter inserted into the motherboard to check for the presence of working signals.

To facilitate the task of finding a faulty component, I will give the most common symptoms of breakdowns of various equipment. When the processor fails, then most often traces of burning are visible on its legs.

In motherboards, the most common failure is the failure of discrete elements, especially capacitors in the VRM (Voltage Regulation Module, which is an LC filter). Yes, and the block itself can burn out. Often, electrolytic capacitors simply swell, which requires their replacement. Also, a common moment is the “knocking out” of transistors in the area of the north bridge, memory modules and VRM. They can be identified by burnt legs and darkening in this area. There are also failures of clock generators and delay lines, as well as burnout of ports.

Also, a sometimes occurring phenomenon is a violation of the contact on the board. This can be caused by not fully placing the expansion card in the slot, bending the board, shorting the contacts on the back of the board to the case, lack of length of wires from the PSU to the motherboard.

In hard drives, the most vulnerable spot is an overheated controller and an IDE connector. A burnt controller can be identified by darkening near the places of its attachment. Overheating of the microcircuit leads to deterioration of the contact between the HDD controller and the HDA. The mechanical problems of the hard drive motor can be identified by the strong vibration of the HDD case when the disks rotate. Massive failures were noticed with IBM DTLA and Ericsson (70GXP and 60GXP), Maxtor 541DX, Quantum Fireball 3, Fujitsu MPG series drives.

In CD drives, the optical-mechanical part most often fails. In particular, the mechanism for positioning the laser and determining the disk. As a rule, such a breakdown is caused by a malfunction of the MSU (system control microprocessor), which generates control signals, as well as the laser reader motor driver, which is responsible for the excitation signal. To check them, it is necessary to measure the output signals at the corresponding contacts of the MSU. A characteristic symptom of a malfunction of the MSU is the lack of movement of the laser reader during the initial power-up. In floppy drives, the most common mechanical failures associated with the lift and clamp of the floppy disk.

Software and hardware diagnostics

If all of the above did not help determine the breakdown, then you will have to move on to software and hardware diagnostics. And in order for it to be successful, you need to know exactly what is the order of turning on PC devices.

So, consider the order of booting the computer.

After the power is turned on, the PSU performs a self-test. If all output voltages are correct, the PSU outputs a Power_Good (P_G) signal to the motherboard on pin 8 of the 20-pin ATX power connector. About 0.1-0.5 s elapses between turning on the PC and giving a signal.
The timer chip receives the P_G signal and stops generating the reset signal applied to the microprocessor. If the processor is not working properly, then the system freezes.
If the CPU is alive, then it starts executing the code written in the ROM BIOS at FFFF0h (the address of the system reboot program). This address contains the command to unconditionally jump JMP to the address of the beginning of the system boot program through a specific ROM BIOS (usually this is the address F0000h).
Execution of specific ROM BIOS code begins. The BIOS starts checking system components for performance (POST - Power On Self Test). If an error is detected, the system will beep because the video adapter has not yet been initialized. The chipset and DMA are checked and initialized, and a memory size test is performed. If the memory modules are not fully inserted or some memory banks are damaged, then either the system freezes or long repeating beeps sound from the system speaker.
The BIOS image is unzipped into RAM for faster access to the BIOS code.
The keyboard controller is initialized.
The BIOS scans the memory addresses of the video adapter, starting with C0000h and ending with C7800h. If the BIOS of the video adapter is found, then the checksum (CRC) of its code is checked. If the CRCs match, then control is transferred to the Video BIOS, which initializes the video adapter and displays information about the Video BIOS version on the screen. If the checksum does not match, then the message "C000 ROM Error" is displayed. If the Video BIOS is not found, then the driver written in the BIOS ROM is used, which initializes the video card.
The ROM BIOS scans the memory space from the C8000h onward for the BIOS of other devices, such as network cards and SCSI adapters, and checks their checksum.
The BIOS checks the value of the word at address 0472h to determine whether the boot should be hot or cold. If the word 1234h is written to this address, then the POST procedure is not performed, a “hot” boot occurs.
In the case of a cold boot, a POST is performed. The processor is initialized, information about its brand, model, etc. is displayed. One short beep is given.
RTC (Real Time Clock) is being tested.
Determining the CPU frequency, checking the type of video adapter (including the built-in one).
Testing standard and extended memory.
Assigning resources to all ISA devices.
Initializing the IDE controller. If a 40-pin cable is used to connect an ATA/100 HDD, a corresponding message will appear.
FDC controller initialization.
The ROM BIOS looks for the system floppy or MBR of the hard disk and reads sector 1 on track 0 of side 0, copies that sector to address 7C00h. Next, this sector is checked: if it ends with the 55AAh signature, then the MBR looks at the Partition Table and looks for an active partition, and then tries to boot from it. If the first sector ends with any other signature, then an Int 18h interrupt is called and the message "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER" or "Non-system disk or disk error" is displayed on the screen.

In general, everything. As for the last point, the errors indicated in it indicate a malfunction of the hard drive (software or hardware). Now you just have to identify at what point your computer stops working. If this happens before the messages appear on the monitor, then the malfunction can be identified by sound signals. The most common sound signals are shown in the table.

It is worth noting that the beeps may differ from the above due to different BIOS versions. If the sound signals did not help determine the malfunction, then it remains only to rely on hardware diagnostics. It is produced by several means.

Hardware diagnostics

The first remedy is very banal, but quite effective. The operation of individual units can be checked by touching them with your hand to check their heating. After a minute of turning on, the chipset, processor, memory chips and video card blocks should warm up. If they seem warm, then this is enough to conclude at least that power is supplied to these elements. With a high degree of probability they should be working.

The second remedy is more scientific and requires some engineering background. It consists in measuring potentials on various elements. To do this, you need a tester and an oscilloscope. It is desirable to have a motherboard layout map as it is multi-layered and the signal flow is not so obvious. It is worth starting measurements with the power elements of the input circuits and stabilizing and shunt capacitors, check the presence of +3.3 and +5 V in the corresponding places on the motherboard, the operation of clock generators. After that, it is worth checking the presence of standard signals at the outputs of the processor socket. Next, check for signals in the slots and ports. The last thing to do is to deal with logic elements (although repairing them is often unwise). To do this, you will need knowledge of port and slot pinouts. This information is given in the tables.

The third and last diagnostic tool is professional hardware diagnostic tools. These include the use of diagnostic cards of the DP-1 type and the PC-3000 complex, created by the ROSK company. The diagnostic board is installed in a free slot of the motherboard, and after turning on the PC, an error code in hexadecimal form is displayed on its indicator. The use of such a board significantly increases the probability of fault localization. The use of DP-1 is designed for the correct operation of the processor, and the CPU fails extremely rarely.

At the moment, in Russia, diagnostic cards, test ROM BIOS and other diagnostic tools are produced by ACE Laboratory.

With hardware diagnostics, it should be borne in mind that in most cases only one device fails, and the easiest way to identify it is by replacing it with a similar one that is guaranteed to work.

As for power supplies and peripherals, troubleshooting in them is a topic for a separate discussion, but a number of tips can be given about monitors. Quite often, an intermediate horizontal transformer fails, which is connected between the terminal and output horizontal transistor. Its main malfunction, as a rule, is a short circuit of the turns. This transformer is part of a high voltage line scanner. This high voltage is applied to the CRT. Therefore, often the absence of a glow on the screen and the absence of a raster indicate the absence of high voltage. Typically, a vertical bar on the screen also indicates a line scanner failure. You can check for high voltage on the CRT by running your hand over the screen surface. If high voltage is applied, then you should feel some vibration or crackle of static electricity.

Software diagnostics

If your computer still turns on, but is unstable, freezes during boot, “falls out” on a blue screen, then this is most often the result of overclocking, local overheating or “buggy” memory, as well as HDD operation errors (these include “ fall" Windows).

The stability of their work can be checked under DOS by booting from a system floppy disk or disk. To do this, use the CheckIT, PC Doctor, Memtest 86, Stress Linux, Norton Diagnostics, The Troubleshooter utilities. For professional HDD testing and recovery, HDDUtility and MHDD should be used, but they only work correctly under MS-DOS 6.22. The first thing to do with them is to check the SMART attributes of the HDD status. You can also use Norton Disk Doctor to diagnose, check, and flag bad sectors.

It should be remembered that a full-fledged hardware check can only be performed under Windows, testing the stability of work in burn-in tests for at least 24 hours. Among such tests are CPU Hi-t Professional Edition, CPU Stability Test, Bionic CPU Keeper, CPU Burn, Hot CPU Tester Pro, HD_Speed, DiskSpeed 32, MemTest.

In general, as you know, it is much easier to prevent an event than to correct its consequences, therefore it is much easier to regularly (at least once every few weeks) monitor the parameters of the voltage output by the power supply, view the SMART parameters of the HDD (Active SMART, SMARTVision, SMART Disk programs Monitor), study the temperature of the processor, check for good cooling and the absence of extraneous sounds. It would also be useful to lubricate the fans with engine oil, at least once every six months.

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