Click on the desktop to bring focus to the Finder. Type shift-command-g (all three keys at once), then enter /Library/Preferences/SystemConfiguration/ in the box and hit enter. You will see com.apple.Boot.plist in that folder.
That was the problem! I looked up how to get to the Library folder and the example had the "~/Library" option. When i tried the other, I found it and was able to get the USB superdrive to work with my macbook pro. Thanks again!