Is your hardware ok? Borrow another speaker from your friend, and see whether they are running on your pc. I have recently fixed my speakers. They had circuit problem. If your hardware are ok, then go to control panel, then sound and audio devices, and check whether your speaker driver is installed. Did you get any driver cd with your speakers. Install your driver. Sometimes, there is plug problem and we are messed up with speaker settings. Tighten your speaker plug. You might have inserted your plug in wrong pin.
