No sound on my laptop

On my laptop there is an icon that has a speaker and then a red cross on it. No sound comes out of my computer- and i cannot fix it no matter what i try. Can someone please tell me what to do. Also i took it to a I.T person and they said something about my sound disk or card? And it would cost over $600 dollars to fix, tell me that there is an easier and cheaper way to fix this!