Sorry for posting in the wrong forum, and thank you for fixing it.
The license key I am referring to is probably what you call User Registration. My point is that I need to duplicate an installation of FS2004 and all the environment that goe with it. I have a second FS license and I guess I need one for FSUIPC as well, or anything equivalent. The environment was developed some years ago and works perfectly well. We don't want to upgrade to a newer version of anything, including FSUIPC to avoid any possible rework, due to some changes in interface or behavior.
That's why I am asking if the older version will work with a new registration key.
Balvenie