I don't think it's your speakers, radio, or anything like that. (If it was, it would affect your whole computer, not just your TB application.)
I've seen similar things like this happen to people several times, and almost everytime, the solution to the problem was simply updating your drivers.

(I'll simplify the "drivers" concept to you through PM. Now, im going to show you ways to fix this problem.)

Click on the start menu.
Click on "Run".
Type in "dxdiag" in the space provided.
Copy what it says there, and paste it here.

This has happened to me when I changed the res of the TB window. Try making your TB window 800 x 600, which is the standard viewing size, and take a screenshot.

Try this first before you go installing drivers and what not.

Corey, thanks alot. it worked.

I had 1366з768 installed because thats my window size.

Also, Firebolty, you've probably sent the PM to Slaughter, because i didn't receive it.