Fallout3 Crash?

I've been doing most fixes relevant to my crashes, so it only crashes when I need to sleep (meaning I get to play for many hours before it crashes), i have no problem with a crash that rare. However, I am currently in Rivet City, and everytime I try to leave the city, it loads halfway - gives me a black screen and then stops working.
I tried to disable codecs, with no luck. Ive done the multicore tweek, no luck on current problem.
Q6600 Quadcore, XFX 8800GTX x2, Realtek sound, Steamversion.

Any mods installed? I had this issue as well. Fixed it by disabling Unofficial Fallout patch, exiting Rivet city and enabling the patch again.

I hope for your own good you're using FOMM to manage mods.

If that's not the case, I suggest installing the Unofficial Fallout patch to see if it fixes the crash.