To be able to reinstall you first need to uninstall your current version.
So go to Start > All Apps, find the Reallusion Hub, then right click it and choose Uninstall. Once uninstalled you should be able to install the latest full version that you downloaded.
Please Note: If you still have problems installing, do try right clicking the installer and choose "Run as Administrator".
Peter
Forum Administrator
www.reallusion.com