I have photostorey delux version 12.0.3.90 (UDC2) installed Windows 10 pro but unable to register or activate after installing on upgraded disk to Windows 11 in the same computer. Any suggestions
The latest version of PS is version 24 so your version 12 is at least 12 years old! As such, and with the increased security, hardware and software requirements of Windows 11, I suspect your only option may be to upgrade to a more recent version of the software, sorry.
However, are you sure you have the latest installer for your product? If you go to your Magix account, log in, go to My products and see if PS 12 is listed in your account. Download any installer shown and try again to install the software, after completely uninstalling the current installation on your computer (see this tutorial for how to ensure everything connected with it is totally removed).
Assuming that you still cannot run PS12, you could email infoservice@magix.net and ask Customer Service whether there is any way by which your current version might be installed under Win 11, but I really wouldn't hold out much hope!
Here is an addition to Jeff's answer. Magix Photostory 2014 from 2013 with a P2 serial number can no longer be downloaded from the Magix servers.
I have tried to download the installation program via My account / My products, but I can no longer do this. If you still want to install it, you could do this from the installation CD. But you can no longer update it to the latest version.