I have a program called LeoCAD installed on one of my non-system partitions. I want to associate this program with the file extensions LDR and MPD. However, I am unable to do so using the Windows 7 "Open with" and "Choose default program" dialogs. I am able to browse for the correct executable, but when I select it the program never appears in the "Recommended Programs" or "Other Programs" lists. Thus I am unable to associate the program with the file extensions or launch the program. How do I fix this?