Sony PCG-VX88 - Manual (Page 72)

Changing the display when connecting an external computer display or projector
When you connect an external display to the VGA (Monitor) port, you can toggle the output between the Liquid Crystal
Display (LCD), the external monitor, or both devices.
Press the Fn+F7 key combination to select a display. See Selecting the Display Mode for more information.
To Press Result
Switch to an external display Fn+F7 Toggles between the LCD, the external display connected to the Monitor port, or both
the LCD and external display.
Connect the external display to the notebook or port replicator before you turn on the unit, otherwise the Fn+F7 key
combination will not work.
Page 72