Thank you for contacting us.
I suggest you checking in the Windows Control Panel if any trial WPF installation has left on your machine. If so I recommend you uninstalling it. You can install its purchased version using our Telerik Control Panel tool if you need it. Note that the WPF demos are shown separately from the WPF product.
I recommend you to use our Control Panel tool for every product manipulation you need, e.g. upgrading from trial to purchased version, uninstalling a product and so on.
Please let us know if you need further assistance.
the Telerik team