11.2 Troubleshooting the Hardware Box
11.2.4 Motherboard-related errors
The motherboard coordinates the proper functioning of the system components. It allows devices to communicate and work in harmony with each other. Troubleshooting a "dead" computer system is a process of elimination. The technician will start from the outside and work down to the motherboard. Unfortunately, if the motherboard is malfunctioning or bad, it must be replaced.

Scenario One
The computer will not boot and appears "dead". The first device that should be checked is the external power supply. Verify that the wall jack is working and that the cable is properly connected to the computer. If computer is still "dead", move the focus to inside the computer case. Visually inspect the cabling. Make sure the motherboard and the drives are connected to the internal power supply. Inspect the mounting of the motherboard. The motherboard should not be touching the metal case. The motherboard is separated from the case by rubber buffers on each mount point. If these rubber buffers are not properly installed, the motherboard could short.

If the problem still exists, the next step is removing expansion cards. Remove each card, and then try and reboot the system. If the computer boots, the expansion card that was removed is faulty. Next, check the drive controllers. Remove them and try to boot the computer. If it boots, the problem can be isolated to one of the drives. If the computer is still "dead", remove any modular video cards. If the computer boots, replace the video card with a known good video card and reboot. If the computer is still "dead", replace the first bank of RAM with a known good stick. If the computer is still "dead", most likely the motherboard needs to be replaced or the power supply needs replaced.

Scenario Two
Dipswitches and jumpers can be found on the surface of most motherboards. These settings might be reconfigured while troubleshooting. For example, on some motherboards, the CMOS startup utility can be entered by a particular placement of the jumpers. If these jumpers are not returned to their original configuration, the computer will not operate correctly. To verify motherboard jumper settings, consult with the motherboard documentation or the manufacturer website.

Scenario Three
An end user receives a "BIOS ROM checksum error". During the POST routines, the POST runs a comparison between the compatibility of the ROM chip and the motherboard. If the POST fails, the end user will receive a "BIOS ROM checksum error". This error signifies that the ROM chip and motherboard are not compatible. The ROM chip will need to be replaced with a chip that is compatible with the motherboard.