You cannot activate it at this point, as there is no "mother ship" for the program to contact. There's no company to communicate with. (Edit: Let me clarify....UEI exists, of course, and there's even a "Nevo" that does some other stuff. But the entire line of Nevo remotes we discuss here has long since been discontinued and all associated company support sites shut down.)
But I am able to use unactivated installations of NSP 3.0. Obviously, we've lost conveniences like online device databases, but with a little more work, we can still do almost everything we did before.
I never used NevoStudio (I started with NSP when the Q50 came out), so I'm only spitballing....maybe there's no way to do it, or an easier way...but I would try the various export options. If you can't export the whole job file as something NSP can open, maybe try exporting just the particular configuration...? Maybe save each of your devices into your personal device library, then start a new job in NSP and import those?
Even if you can't carry over the whole job or configuration, I'd think you can save the devices. It's still tedious if you have to reconstruct your control setup, but having your device command sets available would make it a lot easier.