IMac won't boot - Failed to load extension com.apple.driver.applemacriscAGP

Question

Hello, so I have an iMac G4 17" (running 10.4) and it was unfortunately not connected to a very good surge protector. The power surged and a fuse blew and now when I try starting it up it chimes and then just sits at the gray screen with the apple logo. Here's what I've tried:
Booting into verbose and single-user modes, this is what happens:
Failed to load extension com.apple.driver.applemacriscPCI
Couldn't alloc class AGP
Still waiting for root device
Still waiting for root device
Still waiting for root device etc.
Booting into Open firmware mode:
I'm able to do everything just fine, including resetting the nvram
Resetting PRAM:
Works fine, chimes when appropriate
Starting from Tiger install DVD:
Works just fine, I'm able to access all the utilities and was able to copy files off to a flash drive with the terminal. I used Disk Utility to repair the drive and repair the permissions, both of which ran successfully. I did a clean install of Tiger and then repaired the drive and permissions. I selected the new install on the hard drive as the default start-up disk. Still it sits at the gray screen and I still get those same errors in Verbose and Single-User modes.
I found the source code (a cpp file) for the com.apple.driver.applemacriscPCI, but don't really know how to compile it and what headers are necessary etc, and even if I did I don't know where I would put it since the problem can't be on the hard drive after I did a clean install. I have not yet tried completely reformatting the drive before an install but doesn't the installer do that anyway?
Any help would be much appreciated.
Message was edited by: Yost Smith

Answer 1

There may be some circuit damage in the computer; due to the surge of power.
Sometimes, a computer and its owner get lucky and when a surge disables a
Macintosh, a reset of the Power Management Unit (PMU) can help restore the
normal functions. Often, when this works, the computer may not go past the
grey screen at all, until the PMU is reset.
Instead of a simple surge protector, my computers are powered through a
backup power supply; an uninterruptable power unit with battery backup.
These also have automatic voltage regulation. Forget common protectors!
On the iMac G4 series, the PMU reset button is under the metal plate on the
bottom and is hard to see. There may be instructions with images available
online, perhaps in Apple Support's knowledge-base. This would also be in
the official service manual in pdf electronic documentation, for a tech repair.
How to reset PMU in iMac G4:
http://support.apple.com/kb/HT1712
You may have to see if the Apple Hardware Test can show error codes and
other hints of hardware damages; and perhaps a tech visit is not far off...
Good luck & happy computing!
edited.