Do other (known) dvds have sound probs on your pc ?
This will rule out if the T&M dvd is dodgy. If not then:-
Look at the sound properties control panel / sounds & audio devices make sure none of the sliders are at the bottom or muted in volume control and that your sound card is the default playback device
Check the speaker connections and that they are switched on, check the volume level on the speakers and the volume level on the Media player you are using.
Try the dvd in a standalone dvd player see if that works.