I would like to set this up for my stepson I have a older pc with Gigabyte GA-7S748. I would like to find out what I need as far as a video card so he can play Halo with it. It has windows xp home and maxed out with 3gb of memory with a 450 watt power supply. Currently with a GeForce 4 Mx 4000 which is ok for normal use but not for Halo. He likes to play online on mine but I need it for work so I built this instead ,I just need a better video card for him. I would like to keep it under $150.00 if I can. Thanks...