Switch Display to External Monitor or to LCD Projector in Windows 7
Other than using the function keys (FN+F5, FN+F7, etc, according to brand of laptop / notebook), windows 7 provides a standard way to switch your computer display from one monitor to another, or to the LCD projector,
Just press Win+P, the menu for switching / selecting display will appear.
Or Go to Run command and type DisplaySwitch then press Enter.
Choose your preferred display. (This is only effect if you have plugged external monitor or LCD projector to the VGA out port of your computer / laptop ).