Xbox 360, XPS 410, and no sound.

Hi all,

 

I need help. I've connected an Xbox 360 to my XPS 410 with the optional 360 VGA cable (monitor's connected to PC with DVI). The monitor is the WFP 2007 and the sound card is the Integrated Audigy (Sigma Tel, Codec...). The speaker is the sound bar that mounts under the monitor. Off the VGA cable are the red and white AV cables that fit into an adapter to fit into the sound card. It's plugged into the Line In (blue port) and the gui shows that it's working and has the green check-mark. I have video but NO sound. I've tried plugging it in in other ports and tried all analog and digital options in the Xbox with no change. The PC's sound work's fine and the Xbox has sound if plugged into a TV. But put them together and it won't work.

 

Any suggestions to resolve this would be greatly appreciated.