Instructions
Compare the game's system requirements with the hardware on your computer. If your computer does not meet the minimum system requirements, the game will typically not be able to boot the game's main menu.
Update the driver's on your video card. Many video card manufacturers will release updates for their products in the form of drivers. These drivers fix several known issues with the product and are available for free, typically from the manufacturer's website.
Reinstall "Fallout 3." Files can become corrupt or be installed incorrectly during the game installation process, so you can always get a fresh batch of files by reinstalling the game.