MP3 File Audio is One Sided

well it might be the mp3 that's messed and only one channel has the audio. You can set your speakers to "mono" and see what happens. Or change it yourself with audacity.

This. If you're using Winamp, you can do Options->Preferences->Playback->Check "Force mono" to force the audio to be played in both channels. If you'd rather change the mp3 itself, you can use Audacity.