How to edit contect menus in registry

I have discovered a number of posts on the web about how to add a right-click context menu entry to all files/folders via the shellex 'folder' in the registry. None of them have had an impact, none have worked. I have been able to do this via the folder options, but I want to make this entry on all files.

Does ANYONE know how to add a program (.exe) to the context menu for all files? Oh, on W2000 and wxp.