>>Let me say, it's not impossible. The problem is, you need to understand the way the installer puts stuff to the registry. And that is complex. Basically you need all the UUIDs from you installer package. (Component IDs, update ID, package ID, name it) The name of the package. The name of components key files.
>>Backup the registry
>>Then you must search for your UUIDs, learn how it interacts and remove.
>>The big problem is, sometimes the UUID are in different byte order in registry, that is least significant byte might be first.
>>
>>I do this once in a decade, so I just know there is a way, but learn the details every time again. I have no better description at hand.
>>
>>You have the old installer package (with the old UUIDs!) or can recreate it? Try to uninstall the whole package ...
>
>I do have the old SETUP.EXE and I have the source. I am not sure if the source has the UUID. More importantly, uninstalling this package on all computers would be a challenge and a big liability. Since these are all customer computers.
>Ideally, if I had the knowledge, I would create a List Bar (similar to the ctlstbar.ocx) in pure VFP. This would make the OCX not necessary.
>Thank you.

If you have the code (and the ISD Express) you have the UUIDs. Open the stuff with ISD, and look up the nodes. I do not use ISDX, but as far as I remember it was like ISD. Open up the nodes in the tree, and check the information on the right hand panel, it should be there. If all fails there is ORCA, but then you need to learn the IS Database. Not straight forward.
Else try to figure out how a clean install looks by installing into a clean VM and check the Registry. It's normally no problem to search for the file names, this will reveal the UUIDs (in both forms, just use your imagination)