Is your stereo a newer style with OSD (On Screen Display menu)? If so, most modern receivers you can go into the settings and select what audio and video port to use when you are on that input. For example, if you have an input for CD and you wanted to run your computer to this input, your receiver or audio unit may automatically be set to draw audio from the Digital Coaxial audio port for that input, you would need to switch this to the standard analog stereo input. Many modern devices offer an array of inputs for a single source, you will only use one of this ports at any given time, you just need to adjust your settings on the audio unit.