No need to uninstall/re-install Cubase (the eLicenser app couldn’t care less whether you actually have Cubase on your machine or not … it is interested only in your USB keys (or soft e-Licenser ).
However, I am unclear as to what you have actually purchased. You were already running a licensed version of Cubase 6, then you purchased the upgrade to 6.5? Or had you not even used Cubase 6 yet?
The activation codes can only be used the one time (at least, once they have been successfully read ), so your original Cubase 6.0 should already be registered, if you have already done that. The upgrade code for 6.5 will be looking for an existing 6.0 license.
The first thing I would try, however, is to re-download and install the latest eLicenser app, then run the Maintenance procedure.
I do have 6.0 and an activation number that does show up on my Elicenser. But I was running 6.5 and and probably didn’t register it. (Stupid move, totally) This confusion is the result of my HD crashing and my backup going South 3 days before that. 6.5 was running perfectly until then.
I can check with the music store I bought 6.5 from and install it over 6.0 I would think getting proof of purchase to Steinberg and getting a new activation code is going to be a long road.
So, why not uninstall 6.5, reinstall 6.0 activate it with my licensed activation code?
I understand there will be compatibility issues between the files on 6.0 versus 6.5.
If you were running 6.5 before, then it has also been activated, without it being activated, ou could not have run it (as writren several times already). Unless you only ran the trial, and the trial period is now over. Then there is now no more possibility for you to get 6.5.