I have been playing New Vegas (which is one of the best games I have played in a while) without a hitch with a total of 20 hours. Suddenly, it crashes at a loading screen and I do a force restart. When I go back in game and go outside, the games frame rate drops big time. I didnt have a problem before. I have tried reloading saves, lowering settings, updating drivers, ect. The only thing I havent done is download the fix file, which I am nervous about doing. Any ideas to fix this?

Update: I verified the files on steam and it said one was reaquired or something like that. If I respond, that means that fixed the problem.