I've had a Macbook Pro for about a year and a half now with no problems. Everything has been great. But the last few months, I've noticed an on and off audio problem. The output sound sometimes "skips" between the internal speakers, headphones, Built-in Output (hdpn), and Built-in Output (ispk). If music or other audio is playing, it sounds like it is stuttering and skipping. When I then open up "System Preferences" and click on the Sound icon, it's acting all crazy, automatically switching back and forth between all the different audio output options. It's totally sporadic. Sometimes a few weeks will go by with it being completely normal, then it will act up again one day. Then it will go away for a while again. It's really frustrating when it happens. Anybody have any ideas what the problem is? Thank you for your assistance.