Unless your speakers are USB, it doesn't look like you have anything for sound plugged in. The pinkish port underneath the blue and green all the way to the right would be your speakers. VGA doesn't transfer sound, so what I would do now is look on the front for a port that has a picture of headphones on it, throw some headphones in that bad boy and see if sound works there.

And my next question would be, has it worked previously?