I recently got fallout 3 goty for Christmas and i loved it. Unfortunately between 1-30 mins of play, the game freezes up. Also, when i shoot any weapon at a certain enemy my game freezes. I tried reloading my save but the same enemy makes my game freeze up. Also, its not just one enemy. It could be a ghoul, super mutant, radroach, mole rat, etc. Any help would be greatly thanked.

PC Specs.

Windows 7 x64 Home Premium
Intel i5-2400 3.10 GHz
Radeon 5500 HD Graphics
4GB of RAM

Open up the .ini file located in My Documents>My Games>Fallout 3. *Do not alter the one in the actual game directory labeled Fallout_Default_ini*
In the FALLOUT.ini find the line

bUseThreadedAI=0
change the 0 to a 1

then below it add the line

iNumHWThreads=2

If you loaded the game into the Program FIles, this will also cause a problem. Uninstall, not delete, the game and reinstall in a location outside of the program files. When you are installing the game, you will come to a screen that will ask if you want a default or custom install. Choose a custom install and direct the game to be loaded outside the program files. I have mine loaded at C:\Bethesda Softworks\Fallout 3.
If you want it directly installed onto the hard drive, at the custom install option, type C:\.