So Halo and cod are easy to run games since there has been 3 more games in the series released since cod. Since your Computer " stupid " i would go with a prebuild computer. And For prebuilt computers i would go with a dell.
http://www.dell.com/content/products...=19&l=en&s=dhs find one that fancys you and we could help suggest one. The XPS series are the gaming destops btw. And do you just walk around and find mushrooms? like? what you walk for km and km fine a mushroom and take it home? sounds silly.... lol well might be fun.