No sound from Precision T5400

I replaced the Dual DVI Video Card with a dual HDMI Video Card and now have had no sound since doing this.  Device Manager shows NVIDIA High Def Audio for Sound and says Device is working Properly. However if I look in Control Panel > Sound it says No Audio devices installed. I've never seen or heard of a Video Card change causing the sound to stop working???  Any suggestions would be GREATLY appreciated!!