How can I get my MacBook Pro's sound back?
I have no idea if this will even work, but it's worth a try.


Download Virtualbox.
Download Ubuntu and install it in Virtualbox.
Check the sound preferences in Ubuntu and see if any audio devices show up.


Let me know if you need help with any of these steps. If you are able to get an audio device, more than likely, there's a problem with your install of OS X.