thanks for your reply John,
I apologise for attaching the Key file, I did so because the copy of fsuipc5 I have installed did not recognise my key file. I have not used FSUIPC 5 for a long time, and have only re visited my copy of P3d v4.5 when I upgraded my PC to use higher settings in MSFS2020 which I have been using since it came out in 2020 with FSUIPC 7. I do not have FSUIPC 5 installed on my old pc anymore. although when I bought FSUIPC 7 I kept version 5 key file. I copied the Key file into the same folder as the .ini file, when I run the installer and ask it to check for existing registrations it returns an error 16, it also errors if I select enter a new key and enter my old registration key. sorry to be a pain but I would like to fly some of my old aircraft in P3D again.