Installation Of Hardware Prob!!!

I installed bot a video card and a sound card. Both are not being recognized, I use windows xp pro with service pack2. I cannot get the driivers installed because it does not recognize my card. I bought a new x800 pro, I tried using both catalyst and omega drivers. The message I get is this "setup was unable to find components that can be installed on your current hardware or software configuration. Please make sure you have the required hardware or software" I have been at this for 2 days no help from ATI!!