Well no disrespect intended at all but I am going to list the obvious stuff that I have seen people, and myself too, do.
1. Do you have your speakers powered on?
2. Are your speakers connected to the power socket at the wall?
3. Is your speaker connected to your PC. Yes - you speak about the jacks not being picked up.
4. Do you have sound enabled in OS?
I hear you mate.
lets get the jacks removed from the equation as a possible issue. You have access to another board that you can test each jack to see if they work correctly? Laptop or mates PC near by?