Bad behavior!
I had ver. 4.2 in my computer.
Installed Ver 5.1 and received an error message that the registration did not work. Then uninstalled the program, assuming it was the previous version that was annoying. Installed again ver 5.1 but now it says the key has already been used and now I’m sitting with an unregistered version though i had a registered ver 4.2 that worked.