Computer broken? That's how you find out what's wrong

A computer system is a complex interplay of all kinds of hardware components, system software, drivers and applications. However, not much has to go wrong to saddle yourself with a petulant or even 'dead' system. If your PC is broken, you should first diagnose the problem as accurately as possible.

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What do we do?

We investigate various possible causes of a computer system that no longer functions (properly). We do this on the basis of a few simple observations. Based on this diagnosis, we then propose the most appropriate remedies.

Tip 01: Diagnosis

If a user reports a computer problem to their company's IT department, there is a good chance that a detailed symptom description will be requested. Logical, because often the solution can already largely be deduced from the symptoms. For example, it makes a big difference whether your system no longer gives any sign of life, or whether you still hear sound signals, see LEDs illuminate or see certain messages – and if so, which ones exactly. So we tailored this troubleshooting article to such observations and classified the potential issues accordingly. If you ever have to deal with problems, you immediately know in which 'problem category' you should be, so that you arrive at the right cause and solution faster.

Tip 02: Nutrition

Most power supplies also have an LED indicator. Then check whether the LED lights up continuously (green). If this LED blinks (for a while), this may indicate a defective capacitor. You could replace it yourself, but unless you're a soldering virtuoso you'd better get a new power supply. Here you will find a 'paperclip test' with which you can check whether a power supply is indeed faulty, but we think it is safer that you get the answer via a 'cross test': connect another power supply to the problematic PC and close the suspected power supply to another computer. If the first works and the other still doesn't, then you know that your power supply is indeed defective. Also check whether all connectors of the power supply are (correctly) attached: here you will find an overview of the most common connections.

Tip 03: Motherboard

It is of course also possible that something has come loose inside the system case, so it is a good idea to check whether all plugs are still firmly on the motherboard. It can also happen that the start button of the PC is blocked. It is best to consult the manual of your computer system for this. Before you open the system case, you should in any case make sure that the PC is completely switched off, that the plug is removed from the socket and that you yourself are 'grounded', preferably with the help of a special anti-static wrist strap - available at computer stores and websites – or by first touching a bare piece of metal from (for example) the central heating system or water pipe.

If everything appears to be in order and the PC still does nothing, there is a good chance that your motherboard is broken. You would do well to have this diagnosis confirmed by a professional repair person.

Tip 04: Monitor

The computer does receive power – for example you hear the fans spinning or LEDs light up – but you don't see anything on your screen. First make sure that the monitor is turned on and that it is correctly connected to your computer via the video cable. It may also be due to an incorrect signal source in the OSD (On Screen Display); almost every monitor has a button with which you get a configuration menu on the screen. Here too, a cross-sectional test can provide a definitive answer: connect your monitor to another PC and connect another monitor to your own PC.

Tip 05: BIOS

Perhaps your system's BIOS has become corrupt or you may have accidentally selected incorrect settings when adjusting the BIOS. This BIOS contains a set of basic instructions that provide initial communication with the hardware; after all, just after turning on the PC, the operating system is not yet loaded. When something is seriously wrong at this level, it can indeed happen that your system just hangs.

In this case, there is little other option than to 'reset' your BIOS. In most cases, this can be done by temporarily moving a 'jumper' on your motherboard: in any case, consult the manual for your system. Or you can remove the CMOS battery for a few minutes after unplugging the power cord. This battery, usually a CR2032 coin cell battery, stores part of the BIOS memory when the PC is turned off. Keep in mind that this operation will return the BIOS to the default settings, but your system can still boot. It is therefore a good idea to check the BIOS settings afterwards and, if desired, to protect the settings menu with a (new) password. The system manual will tell you how to get to this BIOS setup menu, but it usually requires you to hold down a certain key when starting your PC (such as Esc, Del, F2, or F8).

Tip 06: BIOS Codes

You may not see an image, but your ailing system may be trying to explain what is going on in a different way. This is often done by means of a series of sound signals or possibly with the help of LEDs. After all, as soon as you turn on the PC, the BIOS runs a number of diagnostic tests and when such a test fails, the BIOS generates a series of beep codes. The amount and speed of these beep signals then indicate where the problem is: faulty RAM, for example, or a faulty graphics card. Check your system manual or google for something like 'beep codes AND . If it is a memory problem, it often helps if you 'reseat' the memory banks: so take them out, blow away the dust and plug them back in firmly. If it turns out to be the processor or motherboard, then a visit to a professional repairman is often the best option.