You my want to try flashing/updating your BIOS before you contemplate replacing your board. Since it can't get back through the BIOS it may well be corrupted.
Exactly. The BIOS is completely independent from your OS or even your hard drive. If you would feel safer, take your hard drive out or unhook it when you flash the BIOS.
Also, be sure to go with the latest BIOS so your mobo will be as updated as it can be.