PC just shut down... ARGH!

More of a comment then a question... but comments are welcome.

PC is an ASUS P4C800EDlx mainboard running 512meg of OCZ DDR533 memory and a
128meg ATI Radeon 9600XT. CPU is a 2.6 P4 @ 3.19 (stable in all benchmarks
since December - CPU never hits 50'C) Enermax 350w PSU.

Played Doom3 for a couple of hours last night without any issues. When I
exited the game the CPU temp was around 38'C so I don't think I was taxing
the machine. Opened my OE to read the newsgroups and about 10 minutes into
that the whole PC just shut off. Not fun.

I could not get the PC to start regardless of what I did. Pulled the power
cable and reattached. Disconnected hard drives. Pulled PCI cards. Reset
CMOS. PC would just not post - no beeps - anything. Once I pulled the video
card I got the standard "no monitor" beeps. I dropped in a Geforce 2 card I
have and the PC is working again. Put the ATI card back in and no more boot.
***ARGH*** I killed my card!

I pulled the Artic Cooling VGA Cooler off the card (no shim). No damage I
can see. Compound right where it's supposed to be. No signs of overheating.
I put the stock ATI cooler back on. Still dead. BAH!!! Left the PC in pieces
for the night (it died 5 minutes before going to bed).

This morning I power up with the ATI card in and it works fine again. (Had
to reset the CMOS settings).

What happened? Nothing was overly warm when I was pulling it apart last
night. I didn't do anything this morning except turn the PC on.