First up building

[NewbieGeek]

i have 200 bucks to build a computer that will run COD4
(i do not want to buy a screen or mouse or keyboard)

 

[Bodaggit23]

That's not gonna happen for $200.

$400 maybe.
http://secure.newegg.com/WishList/PublicWishDetail.aspx?WishListNumber=11343811