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First of all, disconnect all drives. You don't need a hard drive or a CD drive or a floppy drive to get into the BIOS. It's best to start a fresh build at the bare minimum. Like in this case, it's more important to be able to get into the BIOS than it is to jump into a Windows installation. If the BIOS doesn't work, Windows won't, either! But that's because Windows takes every opportunity to not work...
The next thing I would try is to unplug the system, and take the mobo battery out. It's a CR2032 button cell. Remove it. Wait 10 minutes. Don't put the battery back in. Plug the system back in. Boot it up. If it works fine without the battery, replace it.
Actually, when it comes to those batteries, one of the first things I do with a new mobo is take out the supplied CR2032 and throw it out! Those things are only $2-3 each, less if you buy them in bulk, which means it isn't worth trouble shooting a stupid little battery! So I just get rid of the darn things and replace them with new ones.