My computer has failed to start up, its power LED, case and processor fans, and the reset button don’t work. Is this caused by a motherboard failure?

Problem

My PC, running Windows XP Home Edition, has failed to start up for some reason, having previously had no problems whatsoever. I have made no hardware or software changes. It locked up while I was using it. I pressed the reset button, but the PC failed to restart. The BIOS makes no beeps because the power-on self tests don’t run. Nothing at all appears on the screen. The case fan, connected to the motherboard, and the processor’s fan don’t revolve at all, and the power LED on the front to the case doesn’t light up. If I press the reset switch, the drives’ LED that shows hard disk CD/DVD drive activity lights up briefly and goes out. However, I can hear the hard drive power up, and the DVD drive’s LED comes on. I don’t have any spare components to swap out. It seems to me as if the cause is a failed motherboard, because of the failure of the fans and the power LED to function. Am I right?

Answer

Unfortunately, the cause could be a failed power supply unit, processor, motherboard, network interface card, modem, graphics card, or a sound card.

Bad RAM memory is unlikely to be the cause, because the fans and case LEDs would work even though the PC wouldn’t start up.

To begin your troubleshooting, open the PC’s case and remove the video card, the sound card, any network interface card or modem, and disconnect the hard drive and the DVD drive – the cables that connect them to the motherboard and the cables that connect them to the power supply. Make a note of where the cables connect to the motherboard so that you can replace them. If you can’t remember where the cables connect, you’ll have to consult the motherboard’s illustrated manual. If any one of those components fail, it shorts out the motherboard and prevents it from receiving power. If the PC is connected to the web via a modem or modem and network interface card, they can be hit by a lightening strike.

If the PC starts up properly, press the key that enters the BIOS (usually the Del key). Now you know that one of the components you removed is the cause of the problem, and it’s a matter of installing alternatives until you find out which one is responsible.

If the PC still displays the same symptoms, you can even remove the DIMM memory modules.

If doing that doesn’t allow the PC to start up, you can try resetting the CMOS memory that contains the BIOS setup information. The motherboard’s manual will show the position of the reset jumper pins on the motherboard. If you don’t have a copy, download one from the manufacturer’s website. Usually there are three pins sticking up near the coin-shaped BIOS battery, with a jumper over two of them. Remove the jumper and place it over the pin that wasn’t covered and the one next to it. Click here! to find out how to do that on this site. You don’t have to restart the PC, merely changing the jumper setting resets the BIOS, because the pins maintain power to the CMOS chip and when you remove the jumper and place it over the alternative setting, the information in the BIOS is removed. The CMOS chip is hard-coded with the default BIOS settings, which are then transferred automatically into the chip’s battery-powered memory. You must then replace the jumper over the pins it covered originally. If there is no jumper there, remove the BIOS battery for five minutes and replace it. Click here! to find out how to do that on this site.

If the problem still remains unresolved after all of that troubleshooting, just in case the power-on switch has failed, remove the cable that connects it to the motherboard and connect the reset switch’s connector to the power-on pins on the motherboard, and press the reset switch on the case. On all ATX PC cases, the power-on switch just has to be shorted momentarily to start the PC. If the PC has no reset switch, you can briefly short the two power-on switch pins with the end of a screwdriver to make the PC start up. You won’t get a shock because a screwdriver’s handle is insulated. If you need illustrated information, the motherboard’s manual will have a diagram that shows where the power-on, reset, and LED pins are located.

If the problem still remains unresolved, it must have something to do with the motherboard, power supply, or the processor. The only way to find out which of them is responsible is to replace each of them in turn. But, since you have no alternative components, you should take the PC to a reputable computer shop for testing, or consider upgrading your PC by buying a new motherboard, power supply, processor, and RAM. If you buy one of the latest AMD Athlon 64 or Intel Pentium 4 processors, make sure that you buy the correct type of motherboard for it, a quality 400W to 450W power supply that has the correct 20-pin or 24-pin power connector, and quality brand-name RAM. Download the motherboard’s manual to find out which kind of power connector is used to connect it to the power supply. Most new motherboards are connected to the power supply by a 24-pin power connector.