How to use stereo speakers instead of computer speakers
Before connecting the stereo to the computer you need to verify you are using the same RCA jack for your computer as you are for your stereo. The stereo plug is larger than the computers jack. If this is the case you need to visit a local retailer such as Radio Shack and purchase a conversion plug. When purchasing this conversion, ensure that you purchase a stereo plug and not mono. You may also need to pickup a cable that is long enough to go from your PC to your stereo.
Once you have purchased this adapter or your adapter for your stereo is the same for your computer, connect one end of your cable into the line out section of your computer's sound card. Connect the opposite end of this connector to the Stereo Line out. Before attempting to use the stereo system, ensure that the sound volume is low before playing any audio.