I've had my aluminum iMac since September 2007. Never had to take it in for repairs or anything. Today, while streaming a flash movie online (that I own, but can't find) from a site full of Flash advertisements, gray shaded the screen, and I got the dreaded "You need to restart your computer" screen. Should I be worried about this, or did it just happen because of the overload of Flash that my iMac was processing? Thanks guys.