I woke up this morning and my Mac Pro won't boot. Very sad. I've had this Mac Pro for 8-10 months. I have OS X 10.5.1, boot camp, and Windows XP SP2 with all updates. I left it on overnight to download my Steam games in Windows. I had shut off both my monitors. When I turned them on this morning nothing. So I held down the power button to shut it down. When I turned it back on I got the Apple logo on the screen and it just hung. A few restarts later and it would kernel panic while the Apple logo was there. So I tried to boot from a CD. I could not eject due to the kernel panic but I held down the option key which allowed me to choose to boot from OS X or Windows. At that point I was able to eject the drive (holding the mouse down didn't work) and pop in the Leopard CD. I tried booting from that but had no luck. I then removed all my 3rd party RAM and nothing... I reset the PRAM and the SMC. Now I don't even get the Apple logo. Just a gray screen. I also tried removing all the hard drives and that didn't help either. At this point I think I have to call Apple and I hope my Time Machine drive is okay. But any suggestions before I do that? Edit: Ohhh... I got the Apple logo back. Now I tried booting from the OS X CD and the little spinny thing spun for a while but now it stopped. I'm going to let it sit for a bit to see if things change. Edit2: OS X still gives me a kernel panic, XP gets to the Windows XP scree with the progress bar then hangs, and I can't boot from CD for some reason... well... I can tell it to but it doesn't. Edit3: About all I can do is zap the PRAM and bring up the boot options menu. Otherwise the screen stays gray. Edit Last: Problem was a faulty motherboard. It's repaired now. Yay Applecare.