Actually, the problem is quite clear. If you have a sound card, then you need to install the driver into the computer. If, however, you don't have a sound card, then try going to control panel, sound and audio devices, click advance in device volume, and advance in volume control, and see if the 1 digit output only is checked mark. If it is, then uncheck mark it and it should work. If this process doesn't work, then there's something wrong with the audio outputs on your motherboard.