Somehow the optical digital audio on my MacBook Pro has turned itself on, and I can't turn it off. It's pretty annoying because it has disabled the speakers. When I stick headphones in, they work just fine (they're regular, analog headphones), but as soon as I take them out the red light inside the port turns back on, and the analog audio opition disappears from the sound preference pane. All that appears in preferences is Digital Out. Has anyone else had this problem? How do I get my speakers working again? Thanks.