the player used to create the project could not be found

I am using CS5 on a 64bit Windows 10 Home computer.  I have been authoring DVDs using Encore for several years and been more than happy with it.  This week, out of the blue, I have been getting the message "the player used to create the project could not be found, defaulting to adobe player" when I attempt to open exisiting files, and a simlar message when creating a new file.  With a new file, Encore simply shuts down when I Ok the message. I have reinstalled the software from CD, tried running as Administrator, to no avail.