From Mobile to Desktop, which Windows template should I use?

I would like to port my game from mobile platforms (wp7, wp8, android, iOS) to the desktop (Windows, probably Mac as well).

I’m a bit confused on which template should I use: Windows or Windows Xaml? What’s the difference?

And will a game built on Windows 8.1 run on Windows 7, or should I include some extra components in the setup?

Thanks a lot