Re: CMOS checksum error
Is your keyboard USB or PS/2? It might be trying an alternate one to what you have at the moment, just in case it responds then (some motherboards do funny things like that when they crash out.)
You say you've swapped the CMOS battery, but on swapping it how long did you leave it out? If it was just a few seconds or so the BIOS may not have cleared so the corrupted one may still be loaded. Try popping the CMOS battery, waiting half an hour and then put it back in. That should clear any corrupt settings.
Incidentally, did anything happen that might have caused this that you know of? Tried to flash your BIOS recently for instance, or installing a new piece of hardware?
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