The BIOS (Basic Input Output System) is used on PCs to test and initialize hardware devices such as hard drives and video cards when your computer starts. It contains software routines that provide the basic interface between hardware the operating system. The BIOS is typically placed in a ROM chip which makes sure that the BIOS will always be available even if you have a disk failure.
Many times motherboard or computer manufactures will update the BIOS software to fix bugs or improve compatibility with new hardware. These BIOS patches usually can be downloaded and then installed into the BIOS which is usually called flashing the BIOS.
The procedure for doing this will vary from computer to computer but there are only a few ways to do it. Some vendors will have program that you can run from within Windows that will do the updating for you. This is the easiest method for updating the BIOS. Other methods include booting to a CD or flash drive. In these scenarios you would download the update files and then copy them to a flash drive or create a bootable CD from an ISO image.
Then you would boot your computer with the floppy, flash drive or CD in the drive and follow the prompts to update your BIOS. Just make sure your computer is set to read from whatever device you are boot order from before the hard drive or else it will just boot into Windows. If you are using a flash drive make sure your computer is able to boot from a flash drive since all of them aren’t.