ask your friend how much main memory he has. if he says 4gig of ram then there your ansure. most vendors and gamers recommended your pc have 4g of ram so that the os and game can load without running out of ram. also have you tired updating your video card and are the game have the newest pacthes.
Black ops is hard on the CPU and ya like you say that2gb ram is hurting big time but even if OP got that ram up to 4gb the C2D CPU would still cause lackluster performance.