if your computer is anything like mine, try start>control panel>sounds, speech, and audio devices>change the speaker settings. near the bottom above cancel and apply, click advanced, then, change it from the drop down bar to stero headphones.
yeah thats with xp...hmm try going to the control panel and find general options for your sound, regular and advanced, and see if theres anywhere u can change the output to stereo...should just take a lil looking