So having recovered from my previous issue, listed in another topic (I'd accidentally deleted Games for Windows Live) Fallout 3 seems to run fine, except it freezes after about 10 to 20 minutes, the time varies, sometimes it lasts only 10, other times it seems to go for abaout 20 or 30 minutes before freezing. Either way it happens.

It's on Steam and the computer is a Windows 7, HP Pavilion Elite HPE-141f, if that helps. I've heard something about the game having problems on computers with more than 2 cores, or whatever, and I did manage to apply a fix for that in the past, but I'm wondering if my rooting around trying to fix the other issue might have undone that. I think my computer has 4 cores.

Do this in both My Games and in the root install

Open the folder 'My Documents' / 'My Games' / 'Fallout3'
Look for and open up the file FALLOUT.ini.
Inside FALLOUT.ini look for a group called [general].
Inside the general group, after all the configuration parameters, just copy and paste the following two lines:

bUseThreadedAI=1
iNumHWThreads=2

Also, go into the Prefs file file and disable the gamepad and rumble, set them to 0

You don't mention what your video card is, that could have something to do with it. If your card is too weak for the game, then it can cause freeze ups because it just can't process the graphics well enough.

Do the fixes ccna says as they should stop freezing. You can use FOSE (fallout script extender) instead of gfwl which will disable it and allow you to use some of the more advanced mods.