Empire total war crashes

Ive been playing empire total war and it keep crashing to desktop on turn 1754 on my save, i tried rolling back a save it didnt work. I then uninstalled and reinstalled it, it also didnt work. I had the same problem in a past save but it was on turn 1757. I dont know whats wrong with it and its ticking me off that i cant finish a game. Empire is fully patched to the latest update and im running it on vista premium 64bit. Is anyone else getting this problem and is there anyway to fix it?

Yes my graphics card drivers are up to date last i checked, though i did mess up my catalyst control center by installing the new drivers but forgetting to uninstall the old 1s first. I havent really gotten around to try and fix it cause im afraid ill mess up lol but i dont think those affect it since the first time empire did this was before the whole catalyst driver thing. My card is a 4850 1 gig if it matters.

When I play, it not only crashes from time to time.. In the midst of battle it slows down so a second on the battle field is about 13 i realtime.. so it is actually not playable in battles as this happens about half of the battles, it just kills the fun out of it.. though I have used the patches that comes automatically with steam (yes I bought the game)... It feels terrible spending almost 100 dollars on it (Norwegian price) I just want to return the game now..