I change the windows , an now I can not active Cubase 8 , says that "The activation code has been already.An activation code can be used only one to download or upgrade a liceense .
It is the same computer , I change just windows , it s same windows 7 . just I reinstaled 
I think that talking to Steinberg support is the only option you have as it sounds like the licence is locked to the old installation…
Mike.
Log into your MySteinberg account and push the big button that says reactivate.
Hi, I had the same problem as you too. I followed the steps in this link (Steinberg Forums) when I switch to my other computer a few months ago, it was working perfectly! But now I recently updated my new computer version to window 8.1 and my Soft license was deactivated again! UGH! I followed the exact same steps I did before but it just doesn’t work this time! The reactivation page kept on showing ‘Please provide a new Soft-eLicenser number’ after I copied the number from the eLicense Control Center and clicked ‘reactivate’. Can someone help me please?
I have the same problem with windows 10 except I don’t know how to get a new eLicenser number. I have not been happy with their tech support. Wish you luck.