The hazards of BIOS flashing
As described earlier, the BIOS is a crucial component of your computer since it is always the first program that runs when you turn the machine on. If the BIOS does not run, the machine cannot boot. Therefore it is very important that a BIOS upgrade is performed properly. If it fails, it can permanently ruin the BIOS, resulting in your computer becoming a door stop. Common reasons for BIOS flashes gone bad are power failure during the flashing process, and flashing the BIOS with an incorrect BIOS version. Because of these dangers you do not flash a BIOS just for shits and giggles, but only if there is a very good reason.
How to fix a ruined BIOS chip
If a flash has gone horribly wrong and the computer fails to boot altogether, the only solution is to replace the BIOS chip on the motherboard with a new one that contains a healthy and correct BIOS. To obtain a new BIOS chip, contact your motherboard manufacturer and give them the model of your motherboard. For a relatively small price ($10-15 plus shipping) they may mail you a new BIOS chip. To install the new chip, you open up the computer after taking appropriate anti-static precautions, identify the BIOS chip on the motherboard with help of the manual, carefully pull the old chip out of its socket, and insert the new chip in its place. Be sure to carefully follow the manufacturer's installation instructions.
However, be aware of the fact that some manufacturers will not sell individual BIOS chips, and some older motherboards have non-replacable BIOS chips. In those two cases you will be forced to replace your motherboard, which is expensive and somewhat of a hassle.
While BIOS flashing requires some care and preparation, it is a relatively simple process if done right. Let's go over the steps of properly flashing a BIOS using a real-world example, the motherboard BIOS in my test machine.
Note: Please keep in mind that the following steps are an example to help you understand how the process works. However, your motherboard and BIOS version are most likely different from mine and you will have to adjust your steps, download files, and command line switches accordingly. Please exercise caution when flashing your BIOS and stop and ask for help if you are not certain.
This page: Basics of CMOS/BIOS flashing
Page 2: BIOS flashing utilities (and precautions)
Page 3: Performing the CMOS flash