Well, it's happened again. I was cruising along and all of a sudden my system locked up solid. I only had gkrellm, gaim, evolution, and firefox running. I was trying to email a local news station and clicked on their Contact link and... wham.. I lost all contact with my computer. (It's not a problem with that website since I can go there now and click on the link with no problem.)
Anyway, no keystroke combination was possible. I had to hit the reset button again. This is like the 4th time it has happened.

I installed the hoary .rc. release (I forget the exact filename) and I've done all the updates.

Doesn't leave me with a warm fuzzy feeling here...

Perhaps listing your hardware and whether or not you disabled APIC and PNP in the BIOS would be a step towards solving it.