So the game just crashes randomly after you've been playing awhile?
Have you had any problems with other DirectX games?
After a restart can you play again for about the same length of time? Is there a difference when you first turn the computer on vs playing when the computer has been on all day?
Are you shutting down all non-essential programs, like anti-virus, before starting the game? Checked for driver updates, etc?
You could try lowering the settings or resolution to see if that makes a difference in the frequency of the crashes. If the problem is resolved you could then start raising or enabling options a few at a time to narrow down which are causing the problem.
It isn't the same problem, but you could try some of the suggestions in the topic below to see if they help.
Game won't start, I need help desperatly