VGA is graphics only.
Looking at the information you have provided, it does not appear to be possible to drive the TV speakers from a non-HDMI external source - i.e., there is no LINE IN.
Unless this is the Component 2 or Composite 3?
Your PC cannot supply a HDMI-compatible interface that also contains the audio signal - yes, you may be able to adapt the DVI to feed the TV's HDMI, but as has already been pointed out, DVI is purely video (as is S-video).
I still think that you would be best served with a decent 5.1 (or 7.1) audio system with inputs from the TVs and the PC. You can still hide the PC - it's the speakers you will see!
SD