Hello,
Sorry to hear you are having issues. I assume you can't installed it because you cannot active it, yes? Please use this guide to review all your activation and deactivate old unneeded activation: https://forums.stardock.com/486311/accounts-and-activation-support-faq#reviewactivations.
If activation is not an issue for you, please be more details on your issue.
Thanks
Basj,
Stardock Community Assistant.