You must have a clean, reliable floppy to start. go to
http://www.bootdisk.com and download the little app for creating a dos bootable disk in Win2k. Its the only way to do it. You cannnot flash from within windows. Since Win2k cant create a bootable floppy, go to the recommended site. The app is called Dr.DOS7x.
make sure you do NOT lose power during a bios flash. It will render your board useless. If ya need more help let me know. I'm always upgrading perfectly fine bioses. =)
-Crimson