27 LED Monitor Thunderbolt sound problems

I have a Mac Pro without thunderbolt, i bought a 27 inch and just bought an adapter to get it working. Its been working fine for months. I recently upgraded to 10.8.2 on a new drive and everything just went to ****. (one of the reasons i didnt want to upgrade)

First, i was having problems with my main account. Not able to open calendar because i didnt have permission (i did have an admin account), the problems calibrating my monitor (said that it could not find the profile) then problems with Terminal saying that i didnt have permission.

So i said **** it, and juts created a new account and it pretty much fixed everything and deleted the old one.

Now, i left my computer on and went out to take some pictures, when i get back and try to import and listen to music, i find out that the music/sound is coming out of my headphones. (i didnt changed it). Asked everyone at my house to see who touched my pride and joy, but no one did.

When ever i try to select Display out, it automatically changes back to headphones. Everything working but the sound. Restarted the computer and nothing. When i unplug the USB from computer it will crash it and restart. Left the computer off and USB unplugged for 15 seconds and still nothing. Tried other stuff that i read online and still nothing.

I did find out that a lot of people are having problems with LED monitors and Lion.

This is a clean install from less than 1 week, from 10.6.8 to 10.8.2 so i know that its not other software interfering.

Hope someone have an idea what the **** is going on with Moutain Lion