Bioahock keeps crashing.?

I have Bioshock for the PC and it crashes at specific points yet it remains to be random.

For instance it would crash when I come into a room with a big daddy and it would crash and restart the PC. The only way I could pass that point is to run further ahead then save the game. If I reinstalled the game, I could go through that part of the game without crashing but encounter the same problem in a different spot.

I thought it was the hardware requirements but now that I have upgraded, It still crashes but instead of restarting the PC it would crash to the desktop. A little better but it stil is no good.

I save the game regularly so that when it crashes I could just resume. But now it crashes as i load the third level so I cannot progress.

I'm desperate. Help please. Thanks.

by the way, my hardware exceeds the minimum specs and grahics is dx10 compatible. The problem exists both in vista and XP.