Imac A1225 27inch 3.06Ghz not booting kernal panic

[michaeld4500]

Hi all, the story so far doesn't boot only to grey screen apple logo wheel freezes.Have tried:

Changing ram
Safe mode no boot
Single user mode repair
Disk warrior in target mode told os could not be save format and reload os
Repairing with osx install disc just froze didn't boot
Formating the HDD and installing osx with target mode
Now just a kernal panic and ask me to reboot.
Holding down the option key and does not show the Apple service disk 3S116

Any thoughts anyone