Guys, I have a mid-year 2010 iMac with Snow Leopard, and called Apple Support I wanted to mirror my computer onto my TV. They stated if I have an Apple TV (which I do) I could do that just by downloading Mountain Lion and using the Apple TV. Well, I did that; I downloaded Mountain Lion and is now my OS, however, I am not getting the Airplay icon on the top right. I was given the following link by Apple, but I don't see the icon: http://support.apple.com/kb/HT5404? At that site it states my Mac has to be "mid 2011 or newer." So, what happened? Any help is appreciated. Thanks! I attached a pic of the icon not showing.