Grey Screen of Doom

Question

I've just been through a diagnostic saga, and I hope this might be useful to someone else.
Situation
Recently my Mac Pro refused to boot. It chimed, but I could do nothing to persuade it past the beyond the grey (gray) screen of doom. I tried booting into safe mode with shift, single-user mode with command-S, verbose mode with command-V, target disk mode with T. I tried holding option to select one of my other boot drives. Nothing. I couldn't start from a disk, either with C or D (hardware test). I reset the PRAM and NVRAM – no change. I disconnected all peripherals, expansion cards and additional RAM. No change.
Remedy
Using my PowerBook, I found one other Mac Pro user with identical symptoms. His local Genius Bar had wiped the drive, reinstalled the OS, and the fault had cleared. The thread implied that some kinds of system corruption can affect the computer at such a deep level that it can't start at all. If so, you have to wipe the disk before you can even re-install from DVD.
I removed each of my drives, starting with #1. In the end, #2 was the culprit, not the boot drive. To me, this changes the focus of blame from the OS to hardware. The failure of one SATA drive prevented the rest of the system from booting. I've never experienced that before.
*_Data Recovery_*
I didn't hold much hope for recovering data. I installed it in a Firewire enclosure, and after several minutes with the spinning pizza, Disk Utility found it, but refused to mount it. It failed to repair. reporting "+Invalid B-tree node size+".
Disk Warrior reported hardware malfunctions, but it did enable me to recover the majority of the data.
Summary
Anyone experiencing a totally impenetrable grey screen of doom should also try disconnecting their hard drive to eliminate either system corruption or failure – which I've not seen in a fault-finding tree before.
G.

Answer 1

Hi JCohen,
Welcome to Apple Discussions
What I believe is wrong with your computer is that your Firmware is corrupted. I don't know why it happened since you were changing network locations, but it might be the way you shut off you computer. I believe if you do an Archive and Install, you should be fine. In order to preform and Archive and Install, you need to have:
Install Disks - You need to have the install/restore discs that came with your last version of OS X (The current version). Meaning if you got your computer with Tiger, use the Tiger DVDs that came with your iBook. If you had Panther and upgraded to Tiger, use the Tiger DVDs. You are going to want to have the Disc 1.
Hard Drive Space - When one performs an Archives and Install, they are basically archiving their current hard drive (Some applications/preferences may not work after an Archive and Install!) and putting it on your new one. You will see a Previous System folder, which has all your files from before your Archive and Install.
Patience - Working with computers can be aggravating and stressful, don't let it get to you. From years of experience I have learned that the more annoyed and aggravated I become, the worse the problem gets. The reason being most people don't think things through nor take their time when they are annoyed. If you notice your becoming stress/annoyed, take a break and relax. When you feel better you can resume working.
I hope that helps,
Jon
PS Please respond back with any questions or comments
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