The engine stops after about 5 mins of gameplay. Nothing else crashes..GRAW2, COD4, PES etc...

I'll grab the log later when I'm on my PC and post it up.

Hey, you may have seen my other posts regarding my audio problem in games. I thought it was directly related to my x-fi card, so I disabled it and I am now using the onboard ac97 sound. The problems with Battlefield 2/ 2142 were fixed, but my sound problem with Crysis still remains. I tried reinstalling the demo but just as before with the x-fi, I get very choppy audio during gameplay and even in the main menu/intro movies. I'm running the game at 1024*768 at all the lowest settings and graphically, the game runs fine at this. Any ideas for the problem?
Also, it would be great if someone could help me with my x-fi problem because it's amazing the difference going back to onboard sound. *yuck
Thanks a bunch.