A computer is a very complex machine. When hardware begins to fail or becomes corrupted, many different symptoms may arise, however not all of them will directly point to the actual problem. Hardware problems can lead to unexplained error messages, poor performance and devices not working correctly or not showing up at all. When a hardware component as vitally important to the basic operation of the computer as the BIOS fails, the computer may refuse to boot.
BIOS stands for basic input output system. It is the very first thing a computer accesses when it is turned on. The BIOS tells the computer all the information it needs for it to run: information such as memory, hardware and basic processor settings. The boot-up process the BIOS uses is called the POST. The BIOS resides in a ROM (Read Only Memory) chip that is installed directly on the motherboard. In most cases, the BIOS chip is installed in a removable socket so it can be replaced. The information in the BIOS can often be updated and changed by performing an operation called a flash.
Since the BIOS is the first thing the computer accesses when booting, the symptoms of a BIOS crash or corruption will be usually evident during the POST. You may see strange error messages or hardware may not be recognized properly. Another symptom of a BIOS problem is the computer's RAM, normally counted during the POST, not being counted correctly or producing an error message during the count. The most common symptom of a BIOS corruption or crash is the BIOS simply refusing to POST. If the computer turns on but doesn't boot any further, you may have a BIOS problem.
Problems with the BIOS may be fixed by checking the settings in the BIOS setup menu. This can be accessed during the POST by hitting the setup button, usually "F2" or the "DELETE" key, when prompted. The ability to access the BIOS setup will generally indicate the BIOS is working properly. Check the BIOS settings to ensure that an incorrect setting isn't causing problems. You can also attempt a BIOS reset by changing the correct jumpers on the motherboard. Refer to the documentation for your specific computer or motherboard for instructions how to perform this reset. If you have just recently attempted a BIOS flash, then the flash might have corrupted the BIOS. Attempting the flash again will usually overwrite any corrupted data from a previous flash and correct the problem. Finally, on many motherboards the BIOS chip can be replaced as a last resort if the chip itself is bad.
Unless the problem is directly related to a recent BIOS flash, the chances of the BIOS chip being the cause of problems is very low. The signs and symptoms of a BIOS crash or corruption are identical to those caused by other hardware failures such as memory or the motherboard. Attempt to rule out specific hardware failures before troubleshooting the BIOS.