Make sure to delete the following after you uninstalled (and before re-installing) and do a restart after:
- "C:\Program Files (x86)\Stardock\ObjectDock"
In the registry:
You can also use a tool like CCleaner on top for temp dirs and such, but this should be enough. It maybe could be Stardock storing licence information somewhere else also or with a server look-up or their new activation method, but in that cases you should do a support ticket.