IMac G5 17" - Won't Start? (HELP NEEDED SOON!)

Question

EDIT 4: (Yes, I'm that impatient. Sorry.) The thing below worked ONCE, but it hasn't loaded since. And we still can not get the Startup Disk to load. (As a side Q, why is it that Safe Mode is the only thing that loads anyway?)
EDIT 3: We tried pressing the Command, Option, P, and R keys. That got the tone to sound! HALLELUJAH! But now it's whining again, is that supposed to happen? And will it take all night? (Most of all, will it overheat?)
EDIT 2: We also tried using Safe Mode. (Once.) It actually made our computer do something - but that something was overheating. (Loud, whirring noise, like it is having a heart attack, like it is going into outer space, pick a description. )
EDIT: I checked Apple's article on this. The one that says to start up from the disc. It didn't even load, so please do not say to do that.
We have had our old iMac G5 for about 5 years now (as soon as 2010 comes, anyway).
Recently we had a problem where it suddenly locked up.
Now, even after removing all non Apple hardware, unplugging it, taking it apart and checking the connections, and cleaning it from the dirt inside, it only loads the Apple logo with the grey start up screen and the spinning icon. After that, it just stops and won't do anything else.
We also tried booting up from the Startup disk, but it simply ejects it. (Which is surprising, since it won't do anything else.)
Can someone please tell me how to fix this, or is it finally dead for good?
BTW, we have bought a new Mac, but we still had all of our old pics and such on the old computer, so it is really quite valuable to us.
So if it isn't savable, is it possible to take those photos of the HD and somehow back them up? (Stupid question, I know.)
Thanks,
SSD~
Message was edited by: Supersoradud
Message was edited by: Supersoradud

Answer 1

If you could get the old Mac to start in FireWire Target Disk Mode
it may be seen by a healthy Mac (via proper FW cable between
them) as an external hard disk drive. In this way, files or items
saved on the old computer's drive may be accessible and could
be archived by the second, healthy computer on CD-R or DVD.
The old computer's hard disk drive need not be able to start up
that computer beyond the instructions in FW TDM to see content.
"How to use FireWire Target Disk Mode"
http://support.apple.com/kb/HT1661
There are circumstances in which a healthy computer
could also be utilized to check or attempt a repair on
a failed one, using the FW Target Disk Mode and the
healthy computer's Disk Utility's 'repair disk' from the
version in the healthy computer's utility folder.
Sometimes a failed hard disk drive may make odd noise, or
some other issue in the computer due to component failure
may cause problems. A failing logic board may mimic other
kinds of issues, depending on where the fault occurred.
{Also, an external enclosure could be bought and the drive
from the iMac G5 put inside, then this drive could be looked
into by the healthy computer; using disk utilities to see if it
could be accessed and some content saved elsewhere.
Be sure if you buy an external hard disk drive enclosure
that it will work with the hard disk drive type from the G5.}
In any event...
Good luck & happy computing!
edited.