App can handle 2gb address space every game

iv been modding fallout3 and was told to do app can handle 2gb address space

Is it possible to do this for all the games or would it screw some up?

All the games? Which games?

like all the games iv got

No, that is a direct modification to the Gamebryo engine used in Fallout 3 known as Large Address Aware Enabler. It does not work in other games, but it has been ported to New Vegas; I belive a TES IV version also exists.