Constant Kernal Panics

Question

I have a faithful iMac G4 that will now now longer boot up.
Usually my computer is turned on constantly, occasionally every few weeks or so I restart it due to software updates or just because I hadn't done it for a while. All these problems started after I turned the computer off and unplugged it for an hour or so while some electrical work was done in the bathroom (new switch for the shower).
The only other thing different about the machine is that about 4 months back we installed a new dvd burner as my superdrive had given up the ghost. An engineer friend who knows his stuff did it for me (with me watching, wincing as he pried apart my machine, It is my baby after all ) and all went fine.
Now after turning the computer off for a few hours, I'm constantly getting Kernal panics during the boot up process, but in differing places. Sometimes it's while the grey apple is on screen, sometimes when the screen has gone blue just after. Once in a blue moon it actually loads the operating system only to kernal panic a minute or two later.
So I booted into single user (after looking on the web) and ran fsck -f and it said there was a segmentation error, I then ran /sbin/fsck –fy after reading official apple support documents and looking around a bit more and found that this is apparently what your supposed to type (i'm not a command line guy) and it said all was ok. Each time I ran it it said the HD appears to be ok.
So I booted up with the Tiger install dvd and it kept kernal panicing again and again (at this point i'm thinking - **** it it's going to be hardware related) finally the dvd booted and I ran disk utility to verify the disk and it said the HD was ok. I decided to do a repair permissions and then went to the bathroom (I was getting ready for work) only to come back to a kernal panic.
I've reset pram multiple times, I've removed 3rd party RAM I had installed when I got the machine a few years ago. That I thought has fixed it until the next day it started Kernal panicing again.
I ran the extended hardware check and there was no problems, I then ran the quick check and it got an error with text coming down the screen about memory address's (i think, I know I should have paid more attention) and the option to type reboot.
So I did and tried again, this time I did the quick test first, and it passed, then I tried the extended and I got the same error.
So I turned it all off, I booted up fine till it got to the desktop where it kernal paniced again.
Now I did a pram resett during boot and when it gets to the grey apple I get a kernal panic and a screen full of text.
So I booted the tiger install disk and wiped the HD (it was all backed up), Hoping that this would help...
Nope I now have a completly blank HD and an iMac that will not install an operating system.
It's just got to be hardware hasn't it? From things I've read it looks to be a logic board problem, any idea how much this would cost me to fix in the UK?
So anyone have any idea's about what I can do?

Answer 1

Hello, 
Those don't sound like Kernel Panics to me. Here are some things to try:
1. Reset the PRAM.
2. Boot from your Tiger Install DVD. From the Menu Bar choose Disk Utility select Macintosh HD on the left hand pane and run Repair Disk and Repair Permissions. Try booting again.
3. Try holding down the shift key after the start-up chime (or there abouts if you still don't have a chime). This boots the iMac in to safe-mode. Go into Apple Menu > System Preferences > Accounts and remove all the log-in items. If you've added any fonts recently remove those too.
It's probably best if you start a new thread as this will attract more attention from the real experts.
good luck and let us know how you get on.
mrtotes