IMac G5 (iSight) kernel panics

Question

I'm having continuous kernel panics with my iMac G5.
I unplugged all external drives/accessories.
I removed additional RAM.
I zapped the PRAM.
I rebooted with different disks (all crash sooner or later -- often sooner).
I ran Techtool pro (in target more) - drive is OK.
( could not run Techtool Pro from its DVD )
I ran the Apple Hardware Test (v 2.5.3) and all (extended) tests passed.
I'm at a loss as to what to try next.

Answer 1

Can you boot from your install disc? If so, run Disk Utility:
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
It may well be that your logic board is failing,although kernel panics are usually, but certainly not always, software problems. but see if you can start up in Single-User-Mode:
(Hold the cmd()+S when you hear the tone and release when you see the Apple logo) this will give you a black screen with text (command-line) wait till it finishes booting up and you have a command prompt(localhost:/root#) then type in (/sbin/fsck -fy) this verifies and repairs your startup drive. If it finishes and reports the hard drive has been modified---repeat the command-line entry as above.
Do that until it report the hard drive is OK. then type in (reboot).
Also see if you can boot in Safe Mode (to "Safe Boot"), do this:
1. Be sure the computer is shut down.
2. Press the power button.
3. Immediately after you hear the startup tone, press and hold the Shift key.
Tip: The Shift key should be held as soon as possible after the startup tone but not before.
4. Release the Shift key when you see the gray Apple and progress indicator (looks like a spinning gear).
During the startup in Mac OS X 10.2 through 10.3.9, you will see "Safe Boot" on the Mac OS X startup screen.
During the startup in Mac OS X 10.4 or later, you will see "Safe Boot" on the login window, which appears even if you normally log in automatically.
To leave Safe Mode in any version of Mac OS X, restart the computer normally, without holding any keys during startup.
If the computer runs well during safe mode, then it is some software to blame, which is often the case for kernel panics. If it still panics, then hardware is to blame.