imac g3 (tray, revision A) os install help

Hi,

The normal recommendation in a case like this would be to look for an original (authentic) Apple system CD, perhaps via an online auction site. Either a model-specific disc for your exact machine or a later retail CD. Do not buy any copies.

http://manuals.info.apple.com/Apple_Support_Area/Manuals/imac/imacemergencyhbk.PDF

You're dealing with multiple issues when attempting to burn a bootable installer disk for a 25-year old Mac. Not all manufacturers' blank CD-R disks are compatible in terms of being recognized by older 24x CD-ROM drives. In the early-2000s, I had better luck using Verbatim's disks that had a bluish/turquoise color on the recording surface, compared to disks having a mirror-like appearance. Rather than attempting to create your own disk and end up with more coasters, I'd check ebay for an OS 8.5 universal installer (retail boxed version) disk, like the one here. Auctions are time-sensitive and this one will close in another day or so. You have to keep checking to find a good deal, but as I discovered when looking, sellers are pricing them like they're gold-plated. The retail boxed versions have universal compatibility, unlike model-specific Restore disks that many sellers claim will install the software on a variety of models. Once you have the OS installed, you can run the Apple System Profiler and verify that the computer had the necessary firmware updates installed at some point. Hopefully, the original 4 GB hard drive has been replaced with something having greater capacity. If you plan on installing OS X, the final version of Panther (10.3.9) is as far as you can go, but Panther was produced on a DVD. That will be the next problem to deal with, because using "Target Disk Mode" to install from another compatible Mac requires a FireWire port, which your iMac doesn't have.