Originally Posted by Freebase Dali

Fallout 3 is pretty CPU and GPU intensive. Usually, with games like that (FPS type games that rely on a baseline of consistent and heavy processing), if your computer doesn't meet the minimum system requirements, then they basically prevent you from playing it because the game will essentially be unplayable anyway. (Although they should be checking this during instalation) If this is the case, then there's nothing you can do about it, short of upgrading the actual hardware that's causing the limitation.

Just to be thorough, what did the box say, exactly?