best way to debug intermittent system freezes?

[Steve Franks]

I've got me a laptop with a very clean, updated 7.1 (stable) install.
Started at 7.0.  Only problem is about every 2-4 hours it locks up
solid - no disk, no keyboard, console frozen (not running X yet,
although it's installed and does boot from startx).

How do I even go about poking into this?  It's my very last M$ win32
system, and in my opinion, win32 needs to go away, so I have a
considerable psychological investment in seeing this thru.

Obviously, no lockups or any other weird behavior when running win32.

I thought it might be thermal, but the system has never overheated
before, and I did crank up powerd without effect.

Best,
Steve