have you tried zapping the PRAM yet?

Try this:
Firmware Restoration CD 1.4
Your Machine ID: iMac6,1

Maybe a dumb question, but does the disc show up in startup manager (hold option while starting up)? And what happens when you try to go to the Apple Hardware Test (hold D while starting up with the installation disc in the drive?)

okie seems i have a similar problem i got an imac from some one who said that it stopped working when he was trying to install windows on his intel imac.
i can boot using the oem installation DVD, i am able to erase a partition called boot camp & i create another partition too i am able to erase that too,
when installing i seelct minimum contents so that it installs faster, but even if i selelct just basic installation which requires only 2.5 GB . it takes atleast 2 days to install & on the second days when i wake up & see it says osx was unable to install few item & advises to re install,
since i got this imac i was only able ot install ones successfully but it got stuck on the last screan to log on to osx & when i restarted it was all gone i had to attempt re installation,
can any one advice what might be the problem,.

can it be a problem with optical drive or the hard disk itself


its intel imac g5 with isight.
2.16 core 2 duo
1 gb ram
250 gb har disk

can it be a problem with optical drive or the hard disk itself

With that kind of slowness, that is what is sounds like to me. If possible, I would try and copy the OSX install disk over to some solid state media (flash drive, etc.)

To All, If you can get any type of OSX booting, verbose mode, etc, try holding down cmd+s while booting, this should boot into single user mode. Also try holding cmd+opt+n+v on boot, this should clear the NVRAM.