be extremely careful when updating the BIOS. Not completing the BIOS flash will render your motherboard a paperweight. You will then have to send it in to get the BIOS reburned on the EPROM.
Most manufactuers have explicit instructions on their websites for updating BIOS files. There is a dos file to do this usually. BIOS updates cannot be done through windows. Use your floppy drive.
basically you type the name of your flash program, followed by the name of the new BIOS file.
LET IT RUN ITS FULL COURSE. DO NOT INTERRUPT.
also SAVE your OLD BIOS. Most BIOS flash programs have this option. Save it to another floppy disk. You might need it if you run into problems.