I've been playing civ 4 for a while now and it's always worked fine. I've had a couple of month's away and the other night it just stopped working. I can play anywhere from 2 to 10 turns and then it crashes to a black screen were the mouse is still visible but nothing else, then it hard crashes and I have to reboot the computer. I've got all the latest drivers for my video and sound cards. I've got a Radeon 9800 Pro and using direct X 9.0c. Any help would be great.