I have read a lot of forums and suggestions, but can't figure out why the game is running so slow. At first it runs perfectly fine, but after a few minutes it is running so slow i can do anything. Even the mouse moves with a delay.

I run a lot of games on this computer and have never had any problems before running them at high settings.

I have tried many different resolution and graphic options. I have downloaded new video drivers. Nothing works.

Windows XP, media center edition, sp3
Intel Core 2 extreme CPU Q6800 @ 2.93GHz
4 GB RAM
nvidia geforce 8800 ultra