Click "Start"
Search for "Control Panel"
Click "Control Panel, App, Press right to switch preview"
Click "Appearance and Personalization"
Click "Search Box"
Type "screen saver"
Click "Change screen saver"
Click "Screen saver" and select an option.
Click "Wait:"
Type "30"
Click "On resume, display logon screen"
Click "Apply"
Click "OK"