I guess a little bit after the discussion we have had at another place.
You and your father used a while the same Condor license. Then you bought your own Pro license with all the planes but didn't unregistered Condor on your pc. Then you activated all the planes with the Condor license of your father that was still registerd on your pc.
Now all your planes are registered on your fathers Condor license. Switching to the new pc you used your Condor license, where you not are able to activate the planes again.
That sounds logical to me.
If your father has no own planes, you should change the Condor key with him.
If your father has own planes and you activated the same planes again, I think it's a system error on Condor side and the Condor team has to fix it. Like you can't activate a plane on two Condor licenses it should be impossible to activate a plane twice on the same Condor license.
If you don't know your fathers key I believe you have to buy the planes again.
To help you a little bit, I will show you the Vintage Series Newbie offer
viewtopic.php?f=30&t=21076#p178639
In your case (flying Condor in two years) I would accept a flight with a Grunau Baby, because I don't believe that you experienced the fun to fly this fantastic glider.