This is the image I get on my iMac 2.4 GHz Intel Core Duo OSX10.5.4. I have repaired permisions and removed all login items. Once I move the cursor or open up a window the screen clears behind the cursor or window etc... It freezes up at least once or twice a day... I started up again and attached another screen, the image was normal on both screens. But alone the iMac still starts up with the pixelated screen. Any suggestions would be appreciated.