Thanks, Hayo, but when I enter the first command in Terminal I get Unexpected argument killAll; leaving defaults unchanged.
Also, I am not sure where the Go menu is.
When I go to Macintosh HD in the Finder, I already get Applications, Library, Systems and Users to choose from. Library has a file for Preferences, and that includes some Apple preferences and also some Adobe, Microsoft and Xrite preferences. Is there another Library that I need to access?