Computer shutting down in bios

My homerolled AMD box (Asrock 970 Extreme4 mobo, AMD 8120, Win7 pro) developed problems booting to windows after several months of inactivity. Can't find the boot file/ boot partition (can't remember which...I'm not in front of it right now). I can go to a cmd prompt and see the files an the C: drive via a dir request, however, so I don't think my SSD boot drive has crashed. In going through the bios setup the computer began shutting down after only a few seconds. It's not happening when I do get it to a Windows repair or installation screen, though, only when in the motherboard setup. The battery's not dead, nothing is overheating, and nothing seems amiss.

Any ideas on what would cause a shutdown only in the bios setup? I can get in for maybe only 20 seconds before it shuts down. Had to change the boot preference so that it would boot from a dvd drive so that's how I found out.

I plan on getting Hiren's Boot disk to see if I can fix the Windows part...I don't really want to lose files by re-installing Windows again...and I'm not sure how the boot file got corrupted to where Windows can't read or find it.