I installed Shutter then removed it, and now Print Screen and Alt+Print Screen shortcuts are no longer triggering screenshots with gnome-screenshot. How do I restore this setting?
Open gconf-editor and change the following keys back to this:
If you don't have gconf-editor yet just install it from the software center.
Go to System->Preferences->Keyboard Shortcuts and see if the entries for 'Take a screenshot' and 'Take a screenshot of a window' are present.
to remove any leftover configuration.