From what you've said, I'd suggest turning off the game on task manager. When did you last save the game? You may have just been playing it for too long - perhaps your laptop overheated. If I were you, I'd turn the game off, give the computer a little break, then play again, but save often. If it keeps happening (freezing) - there's lots of threads about things to try to fix it in the Technical Help section, and we can help too.