Greeting Card Magic has been developed by the Cosmi Corporation that was acquired by Valusoft. Many of the programs that have been developed by that company have been retired, and, unfortunately, this is the path followed by Greeting Card Magic as well. It won't work on Windows 10 anymore, but you have the possibility to install one of the supported operating systems to run the program. It can be achieved with the help of VirtualBox.
Note: To install Windows in VirtualBox, follow the available guide and make sure that you have a Windows XP installation disc.