Imac wont boot from hard drive or disc

[Fatjim]

Please help I am well and truly stuck

I have an imac G5,2. I recently tried to install windows, part
waythrough installation I tried to cancel. Cancellation was taking
agesso I switched off the machine. Now when I switch the machine on
thereis just a blank white screen.

The mac wont boot from the hard drive,or from the installation disc. I
have tried booting with all the reccommended boot key combinations,
zapped the PRAM, and VRAM. I have tried running the firmware
restoration disc. Nothing gets a response.The mac wont open firmware
on start up.

The only things that get anything other than a blank white screen
are-

If I press f1 on startup I get a globe on the screen but thats it

If I press X on start up I get a black screen with a white dash on it.
(I cannot type anything)

And most strange I have a backup copy of the operating system on a
DVDwhich was not burnt as an image copy DVD but burnt from the opened
programme. If I put this in and press option on start up a disc
appears with the instruction to EFI boot. When I try to EFI boot with
the disc in the apple appears and the cog showing its trying to bootup
but it doesnt boot. This only happens with this copy not with the
orignal disc.

I was considering opening it up and removing the battery, hoping to
restore everything to factory settings, but this is not
straightforward. The instruction on the apple site for changing the
battery on G5 is not for the plastic G5,2, which doesnt open from the
back. I am concerned about damaging the camera when opening it up.

Any advice would be much appreciated

 

[Egidio]

Even the installation disk? Have you tried to start with the installation disk and holding down the C key? I assume the installation disk you refer to is the original that came with the iMac.

 

[asharom]

This is *exactly* what's happening to my Intel iMac at the moment!

A pity no one's been able to post any solutions.

I'll bring it to the service centre of course, but if it's something that can be fixed at home, I'm all for that.

At this stage, I'm happy to wipe the drive, reinstall, and recover from TimeMachine.

 

[ProblemChild]

Suggestion about the copy installation DVD. Might it be because the firmware is ruined that it won't recognise the original but will recognise the copy? There maybe characters in the CD header (if there is such a thing) that tell firmware how to treat it, whereas without those characters it just starts reading the disc?
Another possibly silly suggestion, I've never used EFI boot, when you get the logo and the cog can you press cmd or apple + v for verbose logging, it might tell you what its trying to do when it hangs.