Need more info. Is the machine rebooting. If so you need to go into Control Panel then System select Advanced then Start Up Recovery. Look down and 3rd (i think box) Unncheck box. When PC crashes you should then crash to blue screen with error codes.
Post error message on here.
Without knowing more info difficult to tell. Could be graphics card drivers/RAM.
Have you added any new hardware? Has the game in question always run ok. Might be worth going to the game website.