1) Any location you want
2) Double-click on the catalog file to open it
3) Yes, I know you didn't ask 3 questions, but you will need to reconnect all the folders once you open the catalog, because the photos will be on D: whereas your catalog thinks they are on C:. Here are instructions for reconnecting: http://www.computer-darkroom.com/lr2_find_folder/find-folder.htm