In Excel cells that link to a PDF file and in Word hyperlinks, the file is loaded into Adobe Acrobat Reader DC instead of my Windows system-default PDF reader. (I have Adobe Reader installed only for occasional "open-with" use.) How can I force MS Office programs to use my default reader instead?

This problem began with a new, "grabby" version of Adobe Reader, recently installed (Adobe Acrobat Reader DC 2015). After I first installed it, whenever used it (i.e. with open-with) it automatically made itself the Windows default reader. I was finally able to defeat its ability to do that (it wasn't easy; don't remember how). However, I still have this problem with MS Office programs using it as the default.

Do you have a solution for this? Is there a Registry setting for this?