I have already searched high and low for an answer to this. I have a mid-2009 MBP and I have no audio, its not working though the speakers or headphones. There is no light on in the headphone jack. I have already reset my PRAM as well. I also deleted the contents of the /Library/Preferences/Audio folder as instructed from another website. I bought the laptop used knowing it was an issue, but I thought it would be a simple fix such as PRAM reset or the headphone jack trick. I have reinstalled OSX twice thinking it might have been a bad install. I'm running Mountain Lion, and everything is 100% up to date. Any help would be appreciated.