trevor basically what happens is that i insert the cd. hit restart as instructed and then it goes to a grey screen which looks like dos on a PC. the message just reads apple firmware 3.0 and then foloows to another line saying ok. i've tried by typing in boot-cd which takes a while. and the next reply is LOAD LIMIT. thats all. i should also let you know that the imac is running 256mb and it only has 6gig. hope you can help.

the cd just says mac osx install 10.3. it'd from another imac i have which was given to me by a friend. the cd worked fine on that imac but not the 333. cheers

What happens if you shut the iMac off, insert the CD in the drive, then restart while holding the letter C ?

If you get the same response, then you may have a poor quality CD disk, or the internal CD drive is not reading CDs properly.

You can try burning a copy of that installer CD, and trying to boot with that copy.

yeah tried that and to no go. i'm justing wondering if maybe i don't have enough room. need to up the HD from 6 gig to ??. but even so i read the forums and people have it running on 190 ram and the same HD space. :(

The space available on your hard drive would not prevent you from booting to the installer CD. A faulty CD, either the installer disk, or the CD drive itself, could be the problem. I vote for the CD drive, you can try gently wiping the laser lens on the drive tray.
Try booting to that installer CD again.
At the Open firmware screen (the text screen that you boot to), type reset-nvram, then press enter. You should get an OK as a response.
Then type reset-all, and press enter.
Your Mac should reboot, so hold the letter C, and see if there is a different response this time.

If this iMac doesn't boot to the CD, by far the simplest way to proceed is to open 'er up, and remove the hard drive. Install in an external FireWire case, and install your OS X while the drive is connected to a different Mac (with a FireWire port, of course, and has to be a PPC Mac)... But, I have access to all this stuff.
Once the operating system is installed, transplant the hard drive into the old iMac, and you should be good to go! Simple!

delta mac... what can i say... one happy old mac lives another day. correct cd tray lens was filthy. just gave it a quick clean andf waa-laa. presto. thanks again. :) :)