What was the original BIOS? What BIOS did you upgrade to?
Have you tried resetting the BIOS via the jumper or pulling the battery (remember that pulling the battery does not work if the computer is still plugged in)?
Have you tried removing the CPU and reinstalling it?
So, here are some possibilities of what could have gone wrong ...
- BIOS did not install properly.
- BIOS you installed is not compatible with your motherboard.
- CPU somehow got fried (really, really unlikely).
- BIOS needs to be reset.
There are some other possibilities, but are just crazy off the wall stuff.