Hi all, I just bought a used Mac Pro running a fresh install of El Capitan 10.11.6 and have found that I can't get any audio to be produced. I have options for Internal Speakers, Line Out, and Digital Out in Audio Preferences. None of them work, including Line Out with headphones plugged in either the front or back jacks. I tried killing the coreaudio process, then restarting, but that hasn't helped. I see it using CPU when there should be audio playing. I don't have startup chimes either, so I can't tell if my PRAM restarts are doing anything. Any ideas? Thanks so much.