If you've limited the cores like i showed you in the video (adding a new command line), you can try changing/adding the command from 'iNumHWThreads=2' to 'iNumHWThreads=1'. Right click your Fallout 3 shortcut (if you don't have one, make one) and click 'Properties' then click on the 'Compatibility' tab and check 'Run this program in compatibility mode for:' and then from the drop-down menu choose 'Windows XP (Service Pack 2)'. If you have the Steam version of the game, do not install it, because Steam automatically updates your games. It will fix a lot of bugs and there is a chance that you will fix your problem. I highly reccomend installing the latest 1.7 patch from the description below. If you have the STEAM version of the game, and you don't have the file called 'fallout.ini', you will have to configure a file called 'fallout_default'.
Fix 1 - Configuring the file if you have STEAM.
