HELP!

I have an original, unmodded version of Fallout 3, through Steam.

I recently got to Tranquility Lane, but now I can't get anywhere. Every time I load this portion, I make it maybe 30 seconds, a few minutes at best, before the game freezes up and stops responding. It never did this before, outside of Tranquility lane, it ran perfectly.

I have attempted to get into the abandoned house, or many houses, in fact, but things as simple as looking at a certain house, or opening a gate, and the thing crashes. I've tried to run it in admin, tried to run it in compatibility. I've tried to reload from an old save and enter tranquility lane again, but to no avail.

I want to see what happens next! Please help, ty!