Got my new PSU and hd 4670 video card today, installed without a hitch, really. Before installing any of the hardware, I uninstalled the current display drivers and shut down my PC. I then put in the new gear, flipped `er back on, and installed the ATI drivers from the disc. Computer rebooted, changed my display to fit my monitor in the ATI options, and tested out a game, which ran like butter. However, there's no sound, and my computer tells me there is no sound hardware installed. Help please.