Q1: I bought a used pcmtuner, What must do to set it up to my name?
Q2: is it possible to buy a PCM tuner used and activate it again?
It is a Yes. You must get the original supplier details from whoever you are purchasing from.
contact the person you bought from, to get seller details, and contact them, but install anyway and complete user registration details etc.
If you don’t need the VZ-Performance server, you can use the PCMFlash software without activation. There are many alternatives to get the Ori files.