Are all of your drivers up to date (video, audio, and any basic motherboard drivers)?
In Vista and Win 7, have you tried running the game as an administrator or disabling UAC?
Verify that you are only running what services, applications, and TSR's you truly need to run prior to running the game.
Try rolling back video drivers to ones that may be more stable.
Make sure you ahve the latest version of DirectX installed.
Are all your drivers up to date (video...
That, ironically, is the very core of the problem if they're using Nvidia cards. The 191 series Nvidia driver is the cause of the problem.
Try rolling back video drivers to oens that may be more stable.
Install the 190.62 drivers, they work fine with the game. I was having the same problem and this solved it for me. Specifically, mine was having issues after the Guide woman contacted me, tho I resolved the problem so that I could continue playing the game so I don't know if there could have been other triggers.