company of heroes hangs then crashes

Hey guys, I just built a new system and this is really bothering me: when I start up a game of company of heroes everything will be fine for 5-45 minutes and then the image will freeze, the music will still play and from there it will either crash to blue screen(which displays for a spit second) or stay in the game and require me to hit the reset button because ctrl-alt-delete won't work. The same has happened in Half Life 2: Episode One. I've played Counter-Strike Source and Day of Defeat Source with no problems and everything else(internet, desktop, word programs) works swell. The performance is out of this world but only for less than an hour. I feel like I have a Ferrari with a 2 gallon gas tank because I only get a short spin around the block before it decides to putter and stop. I have the latest Nvidia drivers(97.92).

Here's my specs:

Clean install of Windows XP Home
Asus Striker Extreme
Intel QX6700
Zalman CNPS9700 LED
Corsair XMS2 TWIN2x2048-9136C5DF
XFX 8800GTX XXX
PC Power and Cooling 1KWSR
TJ09 Black w/ window
Plextor 760A
Creative X-Fi XtremeMusic

hey i exactly have the same problem with company of heroes and CoD 4. Did u ever find an answer to that problem?