Before you do any of this, verify the powersupply is OK with a meter. If it's screwed up, it can cause all kinds of weird stuff to happen. If you can't check it, I'd go as far as to clear the CMOS, any further than that would be dumb if it was the powersupply. before you flash the bios, check the powersupply, replace it if you have to. Flashing the bios with bad power is a STUPID thing to do. Then if the powersupply checks out, or the new one still does it, go ahead and try that.
Not good, I hope the bios chip is in a socket!!! Ummmm, I really hate to say this, but I think the bios chip might have gotten roasted! So, first thing I would try is clearing the cmos, disconnect power from the PC, including periferals, and anything with batteries when you do it. If there isn't a jumper, put a penny in the battery holder on the mobo. That will clear it, AGAIN, disconnect ALL power first, failure to do so can hose the bios chip. Then see if it still does it, I have a feeling it's really hosed bad though. Now, the next thing to try, which I think will PROBABLY KILL THE BIOS CHIP COMPLETELY, is to flash the bios with whatever one you like for the board. Now, the odds are not good that this will work, I think the chip is DAMAGED. It will probably spit out some sort of error in the middle of the flash. Now there is a chance it's just corrupted, and a flash will fix it. Now if the chip dies, I hope it's in a socket. You can either order one from badflash.com, or deal with the manufacturer. If it's not in a socket, maybe you can get somebody to solder a socket on the mobo for you, and you can order a bios chip still. If it was a cheap mobo, CHUCK IT!
That sux, I hope it's just something stupid, maybe the PSU, or bad data stored in the CMOS. Good luck, you'll need it! :o :eek: