When I go to localhost631 I see CUPS main menu, but when I click on any item I get message "404 not found." I encountered this after a large upgrade that took place yesterday (I'm running 15.1.1), after which all printing failed. Deleted old printer and tried to set up new, but when I hit continue after finding the network printer I received message "CUPS error." That's when I tried localhost631, and got error described above.

Related question is, if CUPS is trashed, is there a way for a relatively non-technical sort like myself to reinstall it?