Levels were working ok until I got to Slaughter House. Graphics got really, really bad. My keyboard controls did not want to work, can't see cursor, could not see weapon I was using. Tried changing to openGL 640x480. Billy Bobs Mini Golf once again started out ok then same thing.
WinXP SP3
Nvidia GeForce GTS450
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz

Help!