mainly your graphics card but then it works back from there like you cant have the best graphics card money can buy if your motherboard doesnt support it and your power supply cant power it also your memory like you've put it has 2gb of ddr2 ram but then it can come down to what speed the ram runs at etc etc tbh im a little out of touch with current top specs but by the sounds of it this pc will be fine for you if your just starting out with gaming or if you just want a decent pc thats quite quick this will be spot on. it comes down to how you look after it if it fills up with crap and junk then it will make the fastest pc in the world slow. yes ideally you want it re-formatting so its all fresh and new there and donr go anywhere near the net on it till its anti-virus/firewalled up to the max keep those up to dat and your laughing. sorry if this is a wall of txt that makes no sense i've put it the best i can