Why does not the computer turn on at all? Step-by-Step Instruction for Troubleshooting

Even the most accurate user is confronted with a situation when his computer suddenly stops turning on. This can be due to a variety of reasons - hardware, software or due to the combined impact of both. How can they be detected? What are the available ways to fix the breakdowns that prevent the PC from booting?

Interpretation of breakdowns

Strictly speaking, the situation in which the computer does not turn on at all, that is, when there is no reaction to pressing the power button, is rare. It is due to a number of reasons, for example, simply because the apartment is off electricity.

Many users understand under the state when the computer does not turn on at all, there is no image on the screen, while the system unit is humming, the bulbs on it burn. There is another interpretation of the problem - there is an image, but there is no Windows boot. In this sense, the user identifies this state of affairs with the fact that the computer does not turn on at all, because the result is the same: you can not work on a PC. We will consider several scenarios taking into account the difference in the views of users on the essence of the problem in question.

The situation when the computer does not turn on when turned on at all, as we noted above - is quite rare. Most often, some or other mechanisms on the system unit still begin to work, but for a number of reasons the further loading of the PC becomes impossible. The architecture of modern PCs provides a mechanism that assumes that in the event of such breakdowns, the I / O system - the BIOS - signals them through sounds similar to a squeak. They can be heard in columns or in small dynamics built into the motherboard. Let's consider their features.

Sound signals about breakdowns

The sounds in question are divided into two types - long and short. If the computer does not turn on and on, you need to determine what the sequence of signals is. Modern motherboard manufacturers most often program the corresponding function of microcircuits in relation to such combinations of sounds:

- if there is 1 long signal and 3 short signals, this indicates that the computer does not find the video card;

- if the user hears long, same and repeated sounds, it means that there are problems with RAM;

- if the speaker issues 5 short sounds, then this may indicate a breakdown of the processor;

- problems with the video card can also be voiced through 1 long signal and 3 short ones.

Note that the use of different formats of signal delivery depends on the BIOS version. How is it shown? For example, in some versions of the BIOS, 2, 3 or 4 short-range signals are signaled about video card problems. If the computer does not turn on and pie in a certain way, then in the BIOS of the Award type, the interpretation of the sounds may differ from the one that is set for the Phoenix I / O system.

Problems with power supply

Consider the case in which the computer does not turn on due to power problems. If the PC does not respond to the press button, the first thing to check is whether there is electricity in the apartment. If it is, you need to check if the protection on the network filter has worked. This happens when you connect to it a large number of devices - especially those that require considerable power. It may be a problem with the power cable of the PC - you need to check whether it is properly connected to the corresponding socket in the system unit, as well as to the outlet.

If the computer does not turn on at start-up, this may be due to the user's inadvertent activation of the switch in the back of the system unit. It is located next to the jack where the power cable is inserted. It is necessary that the corresponding element be in the on position. Also on some PCs there is support for several types of alternating current, for example, at 110 and 220 volts. To work in each of them, you must switch the corresponding switch to the correct position.

Problems with the power supply

Another possible reason that the computer does not turn on at all is a power supply failure. Electricity in this case is fed to the PC normally, but the corresponding component responsible for its distribution does not work. It is not recommended to diagnose the functionality of the power supply unit without proper equipment - it is better to contact the specialists immediately.

But it may well be that the system unit of the computer does not turn on due to a power failure, which the user can completely eliminate by himself. The fact is that the power supply unit sometimes triggers an internal protection mechanism against voltage changes. If there is a jump in the electrical network, the corresponding elements in the PC system unit are triggered and do not start the power supply to the microcircuits. This lock will remain in effect until the user discharges the capacitor responsible for the operation of the protection system. To do this simply - you need to remove the power cord from the socket of the system unit, wait a few seconds and put it back. If the problem was in the protection operation, the PC will start to boot normally.

Replace the battery

Among the possible reasons that the PC refuses to respond to the power button is a failed CMOS battery that is located on the motherboard. Its shelf life is about 5 years. Therefore, it is perfectly normal that after this period it can cease to function. Note that this problem does not appear immediately: it is usually preceded by some problems with the launch of the PC, spontaneous malfunctions in the system time settings, computer boot through time.

The CMOS battery is quite easy to replace - it makes sense for professionals to contact inexperienced users, those who do not want to inadvertently damage their computer due to the lack of significant skills in working with hardware. The element in question is, in fact, like a battery, but very flat, like a small coin. It can be located in different places on the motherboard. An example is in the photo below.

Remove the battery using a thin screwdriver. It is better to take it with you to the store as a sample and ask the seller to issue exactly the same, but released recently.

When the "iron" rushes

If the computer does not turn on, problems can also occur in other hardware components of the system unit. For example, it often happens that the design of the actual start button of the system unit is deformed. As a result, the corresponding element simply can not close the necessary contacts on the motherboard, so that the computer starts to boot. You can also start the system manually by finding the Power connector on the motherboard and carefully closing the contacts on it with a screwdriver. Of course, it is better if the specialist does it.

On the PC motherboard there is a large number of capacitors, transistors and other elements, each of which is important for the stable operation of the PC. If the computer does not turn on at all, the reasons may be that any of the relevant components are out of order. Obviously, only an experienced specialist will be able to detect it. But with the exception method it is quite possible to try to calculate this problem, making sure that it's not a matter of power supply, not in the power supply unit and not in the power button.

We have considered the main reasons why a PC may not respond to the power button at all. We will now study the situation in which the computer turns on, but does not start, that is, there is no picture on the screen, or it is, but it does not give anything from the perspective of PC operation.

Noises without result

Consider the first option, when the system unit is working, but the image does not appear on the screen - it flashes. This situation can be due to several reasons.

The most common factor of why the computer monitor does not turn on is problems with the graphics card. This is a fairly sensitive component, mainly due to the susceptibility to overheating. The video cards usually have factory coolers, but the increased load on the corresponding PC component may require significantly more powerful cooling systems.

If the computer screen does not turn on, then it's quite easy to check what type of device it has stopped functioning. You need to connect a different monitor to the PC, or, on the contrary, connect the current display to any third-party device. It happens that there are problems in providing a contact between the monitor and the system unit - the wire was twisted or, for example, the plug was clogged. And in this case, there can be an interesting effect - another monitor on the computer under test does not work because the dust is hammered into the video connector on the system unit, and the current display does not work on a third-party device due to clogging in its elements.

Another reason for the situation in question, when the computer does not turn on (the coolers are working, and nothing is displayed on the screen), - problems at the motherboard level. As we noted above, it has a large number of components. Many of them are responsible for the processing of video signals.

Why does not Windows start?

What can the situation mean when there is a picture on the screen? The fact that, at least in the PC, there are a processor, RAM, video card and main chips. That is technically the computer is ready to work, but for some reason it can not start the operating system. Scenarios that reflect a breakdown may in this case be as follows.

Suppose, before the eyes of the user the following picture: the computer does not turn on (the screen works), and this is expressed in the fact that instead of loading Windows - the inscriptions on the screen. In this case, it is extremely important, what type of message pops up, what they are about. There may be several basic options.

There may be problems with the hard drive. In this case, the screen will display a message like "Reboot and Select Proper Boot Device" or "Disk Boot Failure".

It is possible that the Windows files for some reason are corrupted, for example, because of a computer virus. In this case, a command line may appear on the screen, but the graphics components of the OS will not be loaded. Note that sometimes on the monitor in case of a failure in Windows, the same inscriptions appear, as in the case of difficulties with the disk.

In both scenarios the problem is quite serious, and you may need to reinstall the OS or replace the hard drive. But it happens that this is a very small failure, for example, associated with an unstable contact of the hard drive's connectors on the motherboard. It is easy to eliminate by checking the relevant elements.

The simplest case is a floppy disk in the reader for flexible magnetic media (although they are considered obsolete, but sometimes used). In many PCs in system settings, no matter how surprising it may sound, an option is activated, according to which OS boot should start from a floppy disk. Not finding an operating system on it, the computer decides that it is not installed at all, and displays a corresponding message on the screen. The floppy disk needs to be removed and try to load again.

A similar situation - the user recently reinstalled Windows or supplemented it with some samples of software from the boot disk and forgot it in the appropriate reader. The system, it is quite possible, will also be configured to start downloading from a CD or DVD drive, and it will always implement it until the person takes out the disk from there. Usually, if there are no system files on the DVD-ROM, then the download continues from the hard drive. But they can be on the media in a form that is hidden to the user, and he may not even know what the problem is when Windows does not boot. Therefore, when you start the PC in any case, you should make sure that no carriers - neither flexible nor laser - are placed in the readers.

If Windows does not boot, then this may also be due to problems in the hardware of the hard drive. To do this, connect the hard drive to another PC as an additional one, and check whether the files are read from it. By the way, it will be useful to make copies of the most valuable data on the other computer.

Another option - Windows can start to boot, but instead of the "Desktop" on the screen will display other images or, again, the command line. This means that the disk is OK, but there are problems with the operating system itself. In this case, it is already very likely that you will need to reinstall the OS.

In case of possible problems with running Windows, the user should always have a boot disk at hand. It can be a corporate installation media from Microsoft or, for example, formed by the computer manufacturer. In the second case, useful system programs can also be located on the disk . This type of media can be done independently, for example, based on free Linux distributions.

Incorrect BIOS settings

It happens that the computer turns on, but it does not start because there are incorrect settings in the input / output system. This may be due, for example, to the fact that the user has installed a new hardware component in the PC, for example, an additional RAM module has updated the video card or even a processor, and the BIOS settings have remained the same.

In this case, the most correct option is to set the options in the default I / O system. To do this, go to the BIOS interface - most often, you need to press DEL at the very beginning of the PC boot, and then find the Set Default Settings or compatible with it. Then select the option Save and Exit Setup or sound like this. After that, the I / O system will record the changes, which include setting the default settings and restarting the PC. If the problem does not disappear, then the reason that the download does not go, in something else. Subsequently, the most optimal BIOS settings can be established by consulting with experienced professionals.

By the way, in the BIOS, you can also fix the sequence of system requests to boot the OS. Above we have considered a scenario in which a floppy disk located inside the corresponding reader can prevent the Windows startup. Settings that are responsible for accessing it are also prescribed in the BIOS. They are located in the Boot Sequence section or in tune with it. As a rule, these settings assume a vertical ranking of the media from which the download will be conducted. If Floppy is located above the others, then it can be replaced with HDD - hard disk.

The PC is turned off

What should I do if the following situation occurs: the computer turned off and does not turn on? The simplest option here is, of course, power outages. But quite often the reason for the other is overheating of certain hardware components. Most often - the processor. When it overheats, the system triggers a protection algorithm. In this case, it is usually hardware, that is, included in the architecture of the processor itself. If the temperature of the main PC chip is higher than the critical level programmed in it, the computer will not turn on.

There are two reasons for this problem - a defective or inadequate cooler, as well as a dry thermal paste - a substance that enhances the effect of the fan. It happens that the user overdid with overclocking the processor - as a rule, this procedure involves a significant increase in the clock frequency of the chip, which leads to its noticeable overheating, which may not be calculated cooler.

To a computer with a processor whose temperature is above normal, it boots up, you need to wait a bit. To avoid this problem later, you should replace the thermal paste, and also improve the cooler. It may also be that the fan is simply dusty. In this case, you need to clean it. By the way, the hygiene aspect is important for most PC components - not only the cooler, but also the video card, motherboard, disks, main fan on the system unit.