2300 MP Projector - no sound

Hi!

I hooked up my new 2300MP projector to my non-Dell computer using the D-sub to D-sub cable and the USB cable as instructed in the user manual.  The projector image is fine  - I have configured the computer to extend the desktop to the projector so I can display PowerPoint presentations.

 

However, I am not able to get sound from the projector.  There is sound coming from the computer speakers, but not from the projector speaker.  I made sure that the projector controls do not have the audio "muted".

 

Any ideas?  Did I miss something?

Thanks!