thats happened to me two. you might have to reinstall the full game. just take all your saved games and moved them to another folder and try to uninstall the game. usually it wont uninstall by itself so you'll have to look for the registration key on your computer and get rid of that so it doesnt think the games installed anymore and you can just delete the game by yourself. then reinstall it. but don t do this without talking to someone else cause i obviously dont know jack.