Warhammer Online and TF2 both crash "at some point" during gameplay (anywhere from 30 sec. to 45 min.).

Specs (of note):
Intel Q6700
2 gig PC6400 RAM
nVidia 9600GT
WinXP Pro 64

Here's what happens:
I'm beebopin' along questing or shooting people and WHAM - the screen goes black, the light on my monitor goes from blue to red (no signal - same thing if my kid shuts down the PC and forgets to turn off the monitor), the internal fans continue to run, the blue power light stays on, the hard drive light flickers a little, ctl+alt+del does nothing, esc does nothing, the power off button does nothing - I have to hit the reset button to reboot the computer. It reboots fine as if nothing happened (no "recover from critical error/shut down message).

I have 1) performed a stress test on the system via the nVidia control panel, 2) run various anti-virus/spybot programs, 3) disabled anything that could be messaging out of my system (HP monitoring, Logitech stuff, even said anti-virus/spyware software).

I'm stumped here. AoC & Crysis are "rig killers" and they run fine on my system, but these two "cartoon" looking games crash me to black!?!?!

Any tips? I posted on the hardware forum, but the answer I received involved testing my RAM & I reall don't think thats the issue. I also checked out my event log & saw a lot of DCOM errors in there. Could they be related or are the errors caused by the crash? In my other post (hardware forum) it directed me to a Yahoo Answers site that I did not understand and made me nervous (it spoke of changing the registry - GAH!).

Any help would be appreciated. I know enough about computers to be dangerous (not to others, but to my pc). If you need me to post anything here, please let me know.

Thanks in advance.

Could you perhaps post the information/error stated in your Event Viewer right after the programs crash?