Also, many store bought computers don't have an AGP slot (they don't like you upgrading from the integrated crap). Make sure your mobo has an AGP slot. And also, like the guy above me said, make sure you have at least a 300W PSU if you are looking at a 9800 Pro. Companies like to put little weak PSUs in the computers to once again stop people from upgrading them. My old HP has a 150W PSU!!