I bought a refurbished 24" iMac in October 2008 and the hard drive failed completely this past week. After I brought it in to the Apple Store for repair I picked it up today and noticed something odd. Right in the center of the screen, from the middle to the right end the screen is visibly darker. Visibly darker as in if you were to put a white screen up you could see a gray block on the center of the screen. Is it possible that they rested the iMac screen on something that damaged the pixels? I'm going to absolutely loathe having to take this thing in for yet another repair, especially one due to their negligence. Any advice?