So I'm not sure what to do here, but when I was using my MacBook Pro (Mac OSX), the sound suddenly stopped working--volume up, no mute, correct output, when i unplugged and plugged in speakers and headphones. I tried rebooting several times... Then I booted into Windows XP via Boot Camp. The sound works just as it should in Windows, which is where I am writing from right now. Any thoughts? Thanks.