I used to play FO3 all the time on my old computer running xp and I never had this problem.
For old times sake I installed FO3 on my new(ish) comp which runs win7 (64bit) but can't get the game going. I know the machine can handle Fallout because it runs Skyrim fine on almost the best settings.
I can launch the game, change settings at the menu etc, and start a new game. It will play the intro movie (the bus in the ruins) and then I get the sound of the heartbeat and the birthing noise and the screen goes white and gets blood spots on it. This is usually where the frezze occurs and I must ctrl alt del to get out of the game.
I have gotten a little further to where Dad wants your name, but the picture froze about 10 seconds before the sound stopped.
I updated my video drivers, have updated the game to 1.07 and tried forcing the game to use one core of the cpu, but now I'm stuck.
Is it true that this game uses external codecs? Because This is a fairly new install of Win 7 and I might not have everything the game needs if it wasn't all included on the DVD.
Otherwise, the only other thing I've seen on this forum is the issue with installing FO3 within the Program Files directory... which yes it is. I will try a new install outside of those directorys after this and post if it helped.