I have this old iMac color and it only shows a folder with ? on screen

Hi,

First of all, have a look at the iMac list at https://everymac.com/systems/apple/imac/. Check which exact model it is. Under the specifications for that model, you may find a link to an Apple manual. There may be a text explaining what to do if/when you cannot eject a CD (for example, if necessary, via a straightened paper clip).

A folder with a question mark indicates that a valid system cannot be found. Apart from the licence question, it is not a good idea to try to use a burned CD made from an ISO file from a third-party site on the Internet. A burned CD may not be properly recognised by the iMac. Instead, look for original (genuine) Apple system discs for that exact computer model, or later Apple retail discs (for all supported models). Information about the pre-installed and maximum system versions can be found in the above specifications.

If the iMac has an old-style CRT tube and is in a translucent, possibly colored case, that would make it one of several PowerPC-based models released between approximately May 1998 and March 2003.

I could be mistaken, but I believe that all of these could run Mac OS 9.2.

As far as Mac OS X goes, some could only go as high as Mac OS X 10.3.9 (Panther). Others could go as high as Mac OS X 10.4.11 (Tiger). Good luck finding used, original installation discs for these somewhere, since AFAIK, Apple doesn't offer downloads of any of these operating systems online.