Open a finder window and go to applications and try to open it from there.
If it is not there then do a spotlight search for system preferences.
If that does not work, try repairing disk permissions.
There is also the possibility that the systempreferences.plist
file has become corrupt.
Open a finder window and go to ~/Library/Preferences/and drag the
com.apple.systempreferences.plist. to your desktop and then restart
your computer - this will replace the file and may fix the problem.
When I go to ~/Library/Preferences/, there is no com.apple.systempreferences.plist.