kernel panic loop on startup PLEASE HELP!

[negativesleep]

I don't know much about macs i was raised on windows but have a macbook and iphone now and my next comp will be a mac, but since I don't have much experience this is pretty tough.
This problem is with a friends Imac, who asked me for help. Replace one macbook screen and everyone asks you to fix their computers...
All of a sudden, his Imac(its a few years old, probably) which is running OSX 10.4.8 goes into a kernel panic on startup. I have tried the following things:

Apple Hardware Test from the OSX 10.4.8 disc showed no problems. I tried running the extended test but it finished really quickly, perhaps I should try running this over and over?


I tried to run the disk utility but when I hold C down on startup it does not go to the kernel panic screen, it just goes to a blank light blue screen indefinitely. Also, I cannot boot into safe mode by holding down shift on startup, I still get kernel panic. I have held option down and tried to choose to boot from the hard drive or the osx disc and though it does try to read the disc and load for a minute but then always panics.

Because I can't even get into any settings of the computer I don't know any specifics about the processor or ram etc since my friend doesn't know much about computers.


I have succesfully cleared PRAM and NVRAM but this did not solve the problem.


Is this a hardware issue? What are my next diagnostic steps?

 

[negativesleep]

anyone? I mean what do you do when the computer can't even boot off the install disc without freezing or kernel panics? should i start troubleshooting hardware? I'm thinking it could be a RAM issue if its hardware?


i should specify that if i just turn the computer on and off it starts to load for a second, then i get the kernel panic everytime.

 

[JediMeister]

If it passed the hardware test with flying colors, it's almost assuredly not hardware, but instead software. First thing to check is whether you have the correct install DVD or not. Make sure it is the one the computer shipped with, not one that was found in a drawer that "might" be it. If you can boot to the install disc, you may have to perform an archive and install, preserving users and network settings. If you still have problems after the archive and install, you may want to consider doing the more comprehensive fix, an erase & install. If still has issues after that, congratulations, you're back at hardware as the sole cause.