Well aside from the fact that my desktop's gone blue screen of death on me it seems that Fallout 3 will randomly crash, as well. The BSOD occurs more than the FO3 crash, but it still puzzles me. Stupid software that my motherboard installed is causing it (the BSOD, that is). I will post any further information you need.

I'm running Fallout 3 with Windows 7 Home Premium 64-bit. I have Steam running as an administrator and in compatibility mode for Windows 7. I believe I have FO3 running as an administrator, but I have it set in Windows Vista Service Pack 2 compatibility mode. I don't know why. I recall messing around with the compatibility modes and can't recollect why I stuck with that one. I downloaded Windows 7 Codec Pack and monkeyed with the audio and video configurations.

Well, I was dealing with excessive crashes until I turned my graphics to lowest settings, but only had blue screen once or twice. Try loading your game, moving the mouse around the screen rapidly so your view spins around, and see if it crashes extra-fast. If so, lower your graphics to absolute minimum, and try the same thing again - I did, and it works fine. Looks terrible though...

If this doesn't work, try running in Windows XP mode - that sometimes works for older games, which I know Fallout 3 isn't, but it's worth a shot.