Cubase 10 PRO upgrade from 9.5 doesn´t load

Hello friends.

Just seem to be having some trouble with Cubase 10 PRO installation. I upgraded from 9.5 , but the program won´t load. I installed from the Steinberg Download Assistent, and I tried changing the folder names of my previous Cubase installations, so that Cubase doesn´t detect them — but thank didn´t work either. After restoring things as they were, Cubase 9.5 continues to work perfectly. Activation Codes and Licenses have been downloaded.

My installation is:

Desktop PC i7
16 GB RAM
STEINBERG UR22MkII USB Interface
Windows 8 Pro

I am waiting for the Steinberg guys on Team Viewer but I would be grateful for any help