[X4U] iMac dead?

[Mary C. Youra]

We killed my mother's iMac G4 (the desklamp variety), and I'm  
wondering if there is any thing we can do to bring it back to working  
order, or if we should part it out? It was running OS 10.4.11, 640 mb  
ram, and had downloaded the latest security update (not the updated  
update, the first one), but it does have an Airport card.

Mom rarely shuts down, uses the iMac for email and web access, with  
fast user switching enabled so Dad can have his own user (but he has  
his own Windows computer, so he doesn't use it). I wandered by the  
house where my visiting Windows sister said it wasn't loading Safari  
pages properly. I sat down and found the Finder unresponsive (and  
noticed the airport bars greyed out, but SMART Reporter was green),  
pressed the power button to restart, but got a grey screen, circling  
to find a system. So, I restarted it in single user mode to fsck. I  
got an error message saying it couldn't find the I/O Directory (or  
something like that), and decided DiskWarrior would be a good idea  
after dinner. I returned with DiskWarrior and husband. We have the  
most current version of DW, which seems to take forever to boot from  
the cd, so I tried the old version first because I'm an idiot (ask my  
DH). The old version of DW seemed to get stuck rebuilding the  
directory, gave an error message that it was going to take a long  
long time because of the problems on the disk, and my husband  
suggested cancelling it and starting over with the new version of DW.  
The new DW eventually booted, and the first thing DH did was the Hard  
Drive test, but DW also said it was okay. It then gave the same long  
long time to rebuild directory message, but I suggested to DH that we  
let it progress over a period of 30 minutes to see what kind of  
progress there might be before cancelling. When there had been  
nothing measurable (on the screen, the bar had not moved, every so  
often we could see it flicker, but that was it), we cancelled that.  
He suggested we try booting from the Tiger disk and archive and  
installing the system. First, though, we tried Disk Utility, which  
alerted us to the fact that Keys were out of order and something was  
wrong with the B Tree. Then, it wouldn't let us install--the disk was  
no longer available--it just didn't show up at all anymore (it had  
before, when we first had started from the Tiger disk, and before we  
pulled down the Options menu). Next, DH thought he could connect it  
to his iBook and use target mode to Erase and Install. It did go into  
Target mode, but balked at the Erase, I assume because the disk is  
all messed up.

I suspect that we were too impatient with DW, or maybe we should have  
run it from an external harddrive, and not the iMac's cd drive. All  
of this restarting with the power button can't have been good for the  
iMac.

Ideas are welcome, plus I'd like to learn something from all of this.