Usually it happens at the most inappropriate moment: The computer hangs, crashes abruptly or even completely fails the service. The following article explains how to systematically isolate, detect and repair Motherboard and other hardware errors in such cases. Suddenly, without warning, the screen is black. Where before, magnificently rendered 3D men were fighting on the virtual battlefield, the BIOS-POST message with minimalistic ASCI graphics now announces a total crash.
If the computer bumps, crashes or restarts abruptly, this can have many causes. The list of potential culprits is long and ranges from simple driver problems to the physical failure of entire components. In order not to lose the overview here, it is important to narrow down the error and then use suitable tools to find the cause.
“The hardware always works faultlessly until software comes into play” is an old saying. However, this insight is not very useful, since computer hardware without software is at best a dust trap. And so even before the operating system or application software interferes with the hardware circuits, there is a lot of software involved.
First there is the already mentioned BIOS, which ensures that the CPU can come into contact with the peripherals during system startup. Only the BIOS – a software – makes sure that the processor can address chipset, memory, hard disks, plug-in cards etc. Accordingly, the BIOS is always the foundation of a computer.
If the foundation is already standing on shaky legs, the probability of a bad outcome is high. If the computer behaves strangely – especially after changes have been made to the hardware or operating system – the first thing to do is to update the BIOS. Don’t worry: Despite the wildest horror stories about failed BIOS updates, this intervention is rather uncritical, if you consider a few points.
Motherboard and BIOS
Rule number one: BIOS and motherboard must match 100%. If the computer still starts, download the free tool CPU-Z. CPU-Z does not need to be installed. Just unzip and start, that’s all. Look under the tab “Mainboard” for the manufacturer and the exact type designation.
Now download the appropriate BIOS update on the manufacturer’s pages of the mainboard. If several revision numbers are available (e.g. “Rev. 2.00”), these must also match. If – contrary to expectation – CPU-Z does not provide any information, you have to open the computer and look for the corresponding imprint on the mainboard. Often this information can be found between two expansion slots, but sometimes also somewhere on the edge of the board.
Now you still need the software that writes the BIOS update to the mainboard. The update tool can also be found on the manufacturers website. If there are several versions available, you can use a Windows tool. The times when it was better to rely on a DOS tool with a cumbersome boot diskette or CD are definitely over.
After a successful BIOS update it is advisable to load the default settings first. Usually this menu item can be found either under “Save and Exit” or directly in the main menu e.g. as “Load Optimized Defaults”. The purpose of the exercise is to bring the entries in the BIOS registers to a functional state.
Sometimes, after the update, registers suddenly point to other memory locations, so that nonsensical entries cause the motherboard to become unstable. Now select “Save and Exit” and only then make changes in the BIOS setup.
Another important tip on the subject of “solid foundations” is: Be cautious about the various overclocking functions of the BIOS setup. Often these turn out to be time bombs. At first, the overclocked computer runs perfectly. However, over time – this can be weeks, months or even years – strange “hangs” or system crashes occur.
Generally speaking, you’ve often forgotten that you’ve turned the speed screws on the motherboard in your youthful exuberance. In any case, our recommendation here is: First reset the BIOS settings to the default values (Default Settings). Often, all problems are solved by themselves.
If the message “CMOS Checksum Error” appears sporadically during the boot process, you can heal the dementia-afflicted BIOS in most cases with a new lithium battery cell. The problem of empty lithium batteries mainly affects older boards.
When you buy a replacement, pay attention to the type. Usually this will be the standard type “CR 2032”, where “20” stands for the diameter in millimeters and “32” for the thickness (in 1/10 millimeter). If necessary, a thinner button cell (e.g. CR2016) with a correspondingly lower capacity will also do.
Defects of the Mainboard
Broken means broken
BIOS settings are of less help against physical defects of the motherboard – only sometimes defective components can be deactivated or bypassed by changing the settings. Unfortunately motherboard defects are not uncommon. The only remedy is replacement. Common reasons for motherboard death are aged capacitors, overheated voltage regulators and sometimes contact problems at expansion slots for plug-in cards or memory modules.
Before you replace the board, as a last resort, you should exclude other causes as far as possible. Try to boot the system in Safe Mode. If this succeeds, there may also be driver problems or a “shot” operating system.
To exclude this case, download the ISO image of a free Linux distribution (e.g. Debian, Fedora or Ubuntu), burn it to a DVD and start Linux without installation from the DVD. If the computer now works without errors, experience shows that the cause is not the mainboard, but rather drivers or your Windows.
If Linux also does not run correctly, remove all plug-in cards – except the graphics card. If the computer then runs correctly again, this indicates a defective plug-in card or driver problems. If this does not help, disconnect all unnecessary USB devices from the computer. Sometimes defective USB devices can disrupt the power supply of the mainboard.
With common Linux live distributions you will find the program “Memtest” in the boot menu. Memtest is a powerful and reliable tool for memory testing. However, a complete test run requires some time. The freeware tool is more or less self-explanatory. If Memtest returns errors, there is definitely something wrong. First you should check the memory timings in the BIOS setup.
Many modern boards overclock the memory in the automatic overcklocking setting “on suspicion”. This can go well, but does not have to. If you have memory problems, try slower timings first. Gladly also mixed modules make problems. Very unfavorable are modules of different manufacturers or designs in dual channel operation.
But even on two different memory channels the use of different memory modules is a potential source of error. Defective memory proves to be treacherous in that it is one of the few defects that can lead to complete radio silence of the motherboard.
As with a defective CPU, neither the obligatory short beep at startup nor a series of beeps will sound as an error message. Except for a short start of the fans, nothing happens.
Speaking of beep codes: If you hear this strange Morse code from the cabinet speaker, a look into the manual of the mainboard will help. Here you should find the corresponding description of the beep code (e.g. one long, two short). Of course, this only works if a loudspeaker is attached to the mainboard connector. Special attention should be paid to the code for an incorrectly recognized graphics card.
Especially with inexpensive computer cases, it can happen that the graphics card is not reliably and fully seated in its slot. But sometimes the slot itself is also the problem. Here you can test the graphics card in another slot – if available on the board.
Bad graphics cards
However, it is often the graphics card itself that leads to issues. A clear indication of graphics card problems is a crash in the final phase of the operating system startup, just before the welcome message appears. In this case, you should first try to start the system in Safe Mode. If the start is successful, remove the graphics card driver (“Control Panel” -> “Programs and Features” or “Software” for Win XP). Restart the system.
Now Windows should start again, albeit with standard VESA driver. Download the latest graphics card driver from the manufacturer of the graphics card chip (AMD, Nvidia, Intel). If the problem occurs again despite freshly installed drivers, this indicates a defect in the graphics card.
If problems only occur with isolated applications – mainly games – you should also install the latest drivers first. In addition, incompatibilities may occur with isolated applications. Often only the appropriate patch from the game manufacturer will help. Sometimes nothing helps at all. You should also consider thermal problems and insufficient power supply. But more about that later.
Power-LED does not light up
A clear indication for a mainboard defect can be the failure of the power LED. This small light is usually located on the front of your PC. First check if the small lamp lights up after the PC has been started. If the power LED does not light up, the mainboard is not necessarily broken. Then check if the corresponding cables are plugged in.
- Unscrew the side panel of your PC.
- On most mainboards, the connectors (so-called pins) are located at the lower end of the mainboard on the right side. Check whether the connectors labelled “POWER +” and “POWER -” are plugged in. (often also “PWR+” and PWR-“) are plugged in.
- If all cables are plugged in correctly, this may indicate a defective motherboard. Alternatively, the power LED may be broken.
Computer does not supply an image signal
If the PC does not provide a picture, the graphics unit is usually replaced. In some cases, however, a defective mainboard can be the reason for the failure.
- If the graphics card does not output a video signal, plug the monitor into one of the onboard graphics outputs.
- If now still no picture appears when switching on the PC and the power LED does not light up, probably the motherboard is defective.
Processor is not controlled
Another hint for a broken motherboard is that the processor is not activated.
- Let the PC run for a few minutes even without video signal and power LED.
- Then switch off the PC and carefully feel the CPU’s cooling fins.
- If these are cold, the CPU is not controlled. Normally this behavior indicates a defective CPU, but in combination with the other symptoms it also indicates a defective mainboard.
Speaker remains silent
When starting the PC probably everyone knows the short beep signal. But what does it mean? The Mainboard Speaker gives error messages to the user via the beeps.
- If your PC does not beep any more, but has done so before at every startup, this is another indication for a defective mainboard.
- If your PC has never beeped before, you may have switched off the notification in the BIOS. In this case, a BIOS reset is sufficient, as the function is activated by default. Please note that after a BIOS reset, you must reset the BIOS time.
- If your PC has never beeped before, you may not have a mainboard speaker. These are already available for less than 5$ in specialist shops or at Amazon.
- When plugging in the Mainboard Speaker, make sure that you plug it in the right way. If you swap the two sides, the speaker will also remain mute.
If all these symptoms occur with your PC, your motherboard is probably defective. A new motherboard can help and is not even expensive. However, when making your choice, make sure that you can reuse all PC components if possible. We will show you how to change the motherboard in another practical guide.