Since I didn't really get a response in the mod sectiom, I will post it here: Hello all, after a year or so I decided to start playing FNV again. I had it still on my PC with a few mods, I also installed a few new ones. I started playing, and entering buildings make my game CTD often. This happens with certain mod intereriors and normal. I am trying to enter the Goodsprings Sewers from A World in Pain, but it always CTD's. Same goes for the Goodsprings School Cellar (Player home). I was able to enter the Prospector Saloon, but leaving it also made my game CTD.

http://www.gamesas.com/topic/1465680-many-interiors-crash/