K7VEMPRO odd problems

I booted to a "BIOS Checksum Error" a few days ago. I went to setup, 'Load
Optimized Defaults' and the system booted fine. But the next time I booted I
got four beeps and the system shut down. I discovered that I cannot boot
when the system overheat auto-shutdown feature is enabled unless I press the
Insert key along with the start button.

Also have a video problem. Booting to DOS, VGA text mode is fine, but at
1024x768 in Windows the image vibrates annoyingly. This was not previously
the case.

Any ideas what could be wrong? This was a test system that has not seen a
lot of use.

nf