I, like quite a few people it seems, was having trouble with this game, specifically regular frame rate collapse that would virtually crash the game, causing me to have to shut it down with taskmanager. I'm not running a big rig, but i can play on high detail with 2x AA with only a slight drop in frame rate when the action gets real heavy.

I'm running
XP home
AMD 64 X2 4200
nvidia 8600 GT
2GB RAM

What i did, was to uninstall the amd dual core optimiser software that comes with the game, and downloaded the version found on the AMD website. While i was there, i also grabbed the drivers for my processor. Both can be found here

http://support.amd.com/us/psearch/Pa...ad%20Processor

When i fired up the rig again, it played smooth as. Most likely because i updated the drivers for my processor. Apologies if this solution has already been suggested, but i thought i'd share it just to show that the frame rate crash problem can be solved in some circumstances.