select the correct sound device?
turn volume up?
plug in and turn on your speakers?
goto the motherboard manufacturer website and get drivers?
find out your soundcard/chip manufacturer and download drivers for it?
If the computer is apple, it should have an picture of an apple with one bite taken off on the screen. If the computer is PC, well...obviously it can have all sorts of apperances, but it won't have an apple on the back