PC upgrade

I have problem, I had to upgrade my PC (as old motherboard damaged RAM and Videocard) so I lost all the data from the HDD - NIS licence as well. When I installed NIS and activated it, it took another licence (now I have just one left). It is the same pc (if I didn’t have to, I wouldn’t upgrade it) but now I have one licence less due to this. How can I get this one licence back?