I purchased my ACD Fall 2011 and it has been working flawlessly. Ever since Monday, it has been emitting a buzzing sound that I initially thought was a bug in my room. It gets louder as I adjust the brightness and is really irritating. Also, the display makes random pop sounds; more like a muted pop sound. Kind of hard to describe. I have AppleCare but am wondering if bringing it all the way to the Apple Store is a waste of time and if they will be able to fix this problem? Anyone else have this problem and resolve it?