I have a 24" iMac, and i'm hoping someone can confirm or deny this... can you boot your iMac in verbose mode (go into terminal and type the following): Code: sudo nvram boot-args="-v" Then reboot. After you hear the chime, the screen should be all white, and then switch to black. Next, on my iMac there is a centered window that appears very briefly (maybe ~2 seconds) and it's talking about com.apple.kernelcaches, and then after that says "loading drivers............", then it switches to full screen verbose mode (white text on black background) and boots. On my PowerBook, I never used to have that centered window during boot up on verbose mode. What does your intel iMac look like when it's booking up in verbose mode?