After postponing for a long time I've finally updated to windows 10 on a new ssd.
I've made a backup of the programs I wanted to keep including ftprush.
Years ago I've bought a key for it. When I did hardware updates in the past and I copied rush from a backup back to the system the registration key was always automatically included.
Now in win 10 this isn't the case anymore and I should put the registration key again.
The problem is I don't have the key anymore.
Is there a way to take the key I have on my windows 7 ssd and fill it in at windows 10 version?