I had my iMac G5's logic board and power supply replaced a few weeks ago because I was having problems with my video supply and I was eligible for the recall, and it's been working fine until now. I woke it up from the screen and hard disk turned off as usual, and I find the screensave frozen, but I could still move the mouse (which had turned into the beachball.) I had to do a hard turn off and then turned the Mac on again, and I saw the grey Apple logo, then it proceeded to the blue screen with the mouse in the top left corner. I could move the mouse, but it left a frozen duplicate at the top left of the screen as well. It never advanced beyond the blue screen, and after a few minutes, the screen went black. I did another hard turn off, then tried it again, and again, and again. i also tried resetting the PRAM, and nothing new happened. I inserted by restore disk, and nothing new happened. Finally I decided to unplug my keyboard and mouse. It did a few roars upon startup, and then went to the grey Apple screen, and then the blue screen, but it scrambled the video. I tried again with the keyboard and mouse reconnected, and I got beyond the blue screen to my wallpaper, and I got this report dialog and could move the mouse, but it quickly turned into the beachball and I couldn't do anything. Finally, I tried a different set of keyboard and mouse, and apparently, it worked. I don't know why. I'm afraid to try my usual set of keyboard and mouse now. Has anybody seen something be fixed like this?