What version of Windows 7? with or without SP1? 32-bit or 64-bit? Home, Professional, Enterprise?
Actually I found the registry tip is very non-invasive, it's more like turning on some extra information display. But you can also use the lnk_parser program (
https://code.google.com/p/lnk-parser/). In a command prompt, navigate to the pinned shortcut directory, and run the program on the emacs.lnk file and look in the output for the app model id. Test it after unpinning Emacs and repinning (but before changing the shortcut target to runemacs) and again after changing the target to runemacs.