I have an HP pavilion with an nVida Motherboard "ABM2n-LA" Win XP media edition and I just installed a Radeon HD 4670 512mb Graphics card. The graphics look great and seem to be working fine but there is no sound. Under the control panel it says no sound devices? I uninstalled it and tried it without the HD audio drive and still no sound. I take the card out and the sound is fine.? Should I get an nVidia 8600 instead?