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Troubleshooting a Computer Motherboard

The motherboard is the computer, so the usual symptom of a failed motherboard is a completely dead system. Fans, drives, and other peripherals may spin up if the motherboard is dead, but more often nothing at all happens when you turn on the power. No beeps, no lights, no fans, nothing.

If you think you have a dead motherboard, think again. The most likely cause of a dead system is a blown fuse or breaker at the wall receptacle. If you're certain the system is getting power and you have just installed the motherboard, it's much more likely that you've neglected to connect a cable or made some other basic error than that the motherboard itself is bad, assuming of course that the problem motherboard is a highquality product.

In a working system, it's very uncommon for a high-quality motherboard to fail other than from lightning damage (see Computer Power Supplies and Protection) or other severe abuse. In particular, it's nearly unheard of for a motherboard to fail while it is running, as opposed to when you start the system. A dead system is more often caused by a dead power supply than a dead motherboard, so the first step to troubleshoot an apparently dead motherboard is to swap in a known-good power supply. If the system remains completely dead with a known-good power supply, it's likely that the motherboard is defective and must be replaced.

It's not uncommon for a motherboard to fail partially. For example, an ATA interface or the embedded video, audio, or LAN may stop working, while the rest of the motherboard functions appear to work normally. It's possible to work around such partial failures; for example, by disabling the failed function in BIOS Setup and installing an expansion card to replace the failed embedded function. We recommend against this practice, however, because a partial motherboard failure is often soon followed by a complete failure.

Configuring CMOS

Each time a system boots, the BIOS boot screen appears momentarily. While this screen is being displayed, pressing a designated key runs the CMOS Setup program, which resides in firmware. CMOS Setup is used to configure BIOS and chipset settings ranging from those as obvious as the Date and Time to those as obscure as memory timings and bus settings.

To invoke CMOS Setup, you normally press F1 (AMI), Del (Award), or F2 (Phoenix). Other BIOS manufacturers use different keys, and some system and motherboard manufacturers modify a standard BIOS to use another key. The key that invokes CMOS Setup nearly always appears on the BIOS boot screen, but if your BIOS boot screen isn't displayed or doesn't show that key, try Esc, Del, F1, F2, F10, Ctrl-Alt-S, or refer to the documentation.

The exact appearance of CMOS Setup and the available options depend on the chipset, the BIOS make and version, and changes made to the BIOS and CMOS Setup programs by manufacturers. For example, two motherboards may use the same chipset and BIOS, but one may give users complete freedom to configure chipset options, and the other allows users access to only some of the settings and uses hard-wired values for other settings.

All BIOSs default to a reasonable set of settings, one that allows the system to boot and function normally. Beyond that, it's up to you to choose settings to configure the system as you want it and to optimize its performance. Some BIOS settings are obvious things like time and date, power management, boot sequence, and so on. Others, particularly those segregated as advanced settings and chipset settings, are anything but obvious. The brief help descriptions provided with them are usually not much help unless you already understand the issue. The primary rule here is if you don't understand what a setting is for, don't change it.

That's easy to say, but it ignores the fact that accepting default settings for obscure options can result in a PC that performs significantly below its potential. PC and motherboard manufacturers differ in how "aggressive" they are in choosing default settings, particularly those for such things as memory timing. Those that tend toward slower, more conservative default settings say, with some justification, that they cannot predict what components particularly what speed and quality of memory a user will install. Choosing conservative settings allows them to be sure that the motherboard will at least work, if not optimally. Those who are more aggressive often PC makers who control the specific memory and other components that are installed and who assume that users want the highest possible performance level and use components that support those aggressive settings.

The first place to look for detailed CMOS Setup instructions is in the manual that came with the computer or motherboard, or on the web page that supports that product. Some manufacturers provide detailed explanations of general CMOS Setup and Chipset Setup options, but many cover only basic BIOS settings and ignore chipset settings entirely. If that's the case with your manual, the best sources of information about advanced BIOS settings are Wim's BIOS ( and Phil Croucher's The BIOS Companion (

Updating the BIOS

When you upgrade a system without replacing the motherboard, the BIOS version it uses can be a critical consideration. Some system features e.g., support for faster or more recent processors, large hard disks, high-speed transfer modes, and AGP are BIOS-dependent, so an in-place upgrade often requires a BIOS upgrade as well. Fortunately, recent systems use a flash BIOS, which can be upgraded simply by downloading a later version of the BIOS to replace the existing BIOS.

The exact method required to update the BIOS varies by motherboard manufacturer and model. Some motherboards are updated simply by copying the updated BIOS file to a floppy disk or CD and booting from it. Other motherboards use a DOS-based "flasher" program that runs from floppy disk and installs the BIOS file when it executes. Intel motherboards support Intel Express BIOS Update, which allows updating the BIOS from within Windows simply by double-clicking an executable file. (Fortunately, Intel also provides floppy disk based BIOS update routines that those of us who run Linux or other non-Windows operating systems can use to update our BIOSs.)

Although updating the BIOS is a pretty intimidating operation the first time you try it or the tenth time, for that matter BIOS updates usually complete successfully if you do everything by the numbers. But if you accidentally apply the wrong patch or if the update process fails through no error of your own, the PC can end up nonbootable. If this happens, there may not be an easy way to recover. Depending on the BIOS, one of the following methods to recover from a failed BIOS update may be usable:

  • A few motherboards have dual BIOS chips. If you corrupt one BIOS during an update, you can boot the system from the other BIOS and reflash the corrupted BIOS.
  • Intel motherboards have a jumper that configures the motherboard for one of three modes of operation: Normal, BIOS Update, and Recovery. To update the BIOS, you must set that jumper to update mode. If the update fails for any reason, you can reset the jumper to the Recovery position, which gives the motherboard just enough smarts to access the floppy drive at boot time and attempt to load a BIOS update from the floppy drive.

More about Computer Motherboards

16 Yorum

The solution to a wrong bios update is to remove the bios chip reprogram with the update and put it back into the motherboard socket.

luisaparente - Yanıt

how do you program it whilst it is removed.? Please reply on;

trevermsga - Yanıt

I would like to know how you reprogram the chip, too.

Kevin Meisenbacher - Yanıt

Same here

Will you Honor me with your knowledge?


iorysrage - Yanıt

if it's serial flash chip, you'll need simple serial programmer (SPI programmer), or built one. it's simple, you'll need some discrete passive elements, like resistors and couple of diodes, and also a serial/ parallel port, or USB-to-Serial adaptor, just check your search engine for details. But if your BIOS chip is parallel programmed, then you'll need more sophisticated microcontroller based programmer and special socket (usually PLCC32) to put flash chip in it. You can distinguish flash type by leg count. If it has 8 legs (DIP-8 package), its serial, if more (like 32 in PLCC32 package), then it's parallel.

Arbeit Ainstein -

@Arbeit Ainstein Thank you for giving us a direction

iorysrage -

Hi....I'm having a problem with my Proline laptop, it starts normally and work for about 15 minutes then after that start beeping for 2 - 3 minutes then shuts down. What could be the problem? Please help

Lindokuhle - Yanıt

it could be overheating. get the cpu cooling fan etc cleaned and lubed.

mjb437 -

Power is nt gng to keyboard mouse monitor no beep Sound fans in cpu working when pc on keybaord light just flash once but after that no power I replace cmos batery also ram re install but no use plse help me


I’m having this exact same problem currently. Any advice out there?

Jeffrey Herold -

What can be the problem if the motherbord goes on but there is no screen display if i put in an graphics card then still no screen pls reply on

renier Cloete - Yanıt

My laptop won't stay on it flashes the boot image and just shuts off sometimes it'll boot up but it randomly shuts off when it starts working and won't stay on again sometimes getting windows 10 problems on boot up is this because of my motherboard? It seems perfectly fine i can't see anything wrong with it

Kuzo - Yanıt

i install a new HDD in my cpu but when install OS in my cpu then it throw a error that OS cant be deploy can u tell me what is the issue

lalit panda - Yanıt

Power supply was tested and found good! But there's no power when I try to power on the desktop. What might've gone wrong?

Clarence Mendez - Yanıt

I have been told I either have Motherboard beginning to fail - or a bios virus? Everything powers up but keyboard and mouse don’t work once past the bios. There are two hard drives - one soldered to the Motherboard which was the original boot drive and is not showing in the bios. The second one is fine. The second one has been wiped with parted magic (cant even use keyboard and mouse in parted magic). I can boot linux live but can’t install due to no functioning keyboard. Have used Kaspersky rescue disk via usb to virus scan and nothing found (used a usb mouse to do that). But it can’t virus scan the non showing disk because it’s not showing. So is this a sign of a damaged or failing Motherboard or possibly a virus on the non showing driving (boot virus?). I would try flashing the bios but am now concerned about transferring viruses via usb so have binned the usb stick and don’t want to keep binning usb sticks!

Jojo Run - Yanıt

Other things I’ve tried - opened it up, reseated keyboard and mouse cables (with antistatic wrist band on). Replaced keyboard with a different one from the same model laptop. Same issue. I bought this laptop second hand knowing the screen had gone (it was on but only partially displaying). Replaced the screen. Screen is fine. Just the keyboard and mouse not working now.

So is it - failing Motherboard, boot/bios virus, or possibly liquid damage to parts of Motherboard? I know that can make a screen and keyboard partly fail. But the fact the keyboard works in the bios is the strange bit.

Jojo Run - Yanıt

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