Complete uninstallation/reinstallation

Ever since I updated to Win 10, I’ve had to run Cubase 8.5 in sys administrator mode in order for j-bridge and a few other plug ins to work properly. Running in sys administrator mode, the program behaves oddly, the most notable change being that I can’t drag audio directly from the desktop anymore. What was initially a nuisance now seems to really hamper my workflow. I think the answer will be to do a clean, full installation of Cubase 8.5 in win 10 - after completely uninstalling it. The problem is, I’ve got installations of every iteration of Cubase since 6. I’m not sure if I need to uninstall them all, then do the full 8.5 installation (I downloaded the complete install from Steinberg), or if I just uninstall 8.5 and then reinstall that. Has anyone had experience with uninstalling and reinstalling Cubase? Advice?