Help: Grey "need to restart" message even from DVD - diskutil mangement framework

[I am Sampson]

Hi,

My 24" iMac (3.06, 4gb, 8800GS) started having weird graphical issues in OSX which based on online research seems to suggest possible graphics card issue. After trying ram sticks individual to check them (no change) I was planning to use a time machine backup, however it has now seemingly for no reason presented another issue.
Reguardless if I boot from hard drive, original 10.5 disk, snow lepoard or the snow lepard disk from my newer 27" iMac after a minute or so of bootup I get the screen go grey from top to bottom and am told to reboot.
This also occurs using safe mode, and booting with option to select boot disk does not work (windows 7 bootcamp also won't load and just stays black).

I can get into single user mode, however I've not been able to use diskutil to erase my disk. All I want to do is try and time machine restore and hope the graphical glitches were just a software issue.

fsck normally finds an error on first run and not second, but does not change anything when rebooting.

I'm hoping discutil will let me format the hard drive and then it might magically be able to boot from an OSX DVD. ANy suggestions on how to get disc util to work?
I'm getting management framework not installed errors and I've tried:

mount -uw /
/usr/libexec/register_mach_bootstrap_servers /etc/mach_init.d
SystemStarter start Disks

However this was found online for OSX 10.3 and I just get folder errors on the /usr/libexec.... part.

Any help would be gratefully appreciated.


Oh, I can also get into hardware diagnostics on original DVD which shows no faults on short or long test.

 

[I am Sampson]

Anyone?

Done more things now... used Target disk mode to try and repair; no luck.
I've even wiped the entire drive, re partitioned and formatted and yet it STILL crashes a few minutes after booting from the snow leopard disk.

Hardware check still insists nothing is wrong... I'm dubious.

 

[wrldwzrd89]

Your conclusion that you have a hardware problem concurs with my assessment of the symptoms. As for what the exact cause is... that's more difficult to determine. You say you can get into single-user mode. Can you run something like Memtest86 on your Mac, say, off a flash drive, to eliminate memory as a possible cause?

If Memtest86 reports no errors, then that leaves as possible culprits (in order of easiest fix):
PRAM (Hold Command+Alt+P+R at startup, leave held until Mac chimes 3 times)
NVRAM (similar procedure to PRAM, substitute the N and V keys for P and R)
PMU (not user-accessible on most iMacs, but is fairly simple to reset if you know how to get to it)
Graphics Card
Power Supply
Motherboard