Missing System Settings after removing some packages
You may have accidentally removed some packages (or some dependencies which caused the package to uninstall). In any case, you may try installing (or re installing) the package ubuntu-desktop. Correct any accidental package uninstallation by:
sudo apt-get install ubuntu-desktop
Uninstall and then reinstall System Settings (unity-control-center) from the Ubuntu Software Center application.
Or run this command in terminal
sudo apt-get remove unity-control-centersudo apt-get install unity-control-center
If reinstalling ubuntu-desktop still doesn't cut it for you, you may be accessing system settings in a wrong way. Try to open them directly from a terminal (rather than a bogus shortcut like I was):
gnome-control-center