Your VAIO computer may not have sufficient video memory to display high resolution videos. In such a case, lower the resolution of the LCD screen. See Changing the Resolution (Size) of the Screen Image for more information.
If you have selected to use an external display using the Fn+F7 keys and the external display is disconnected from your VAIO computer, the computer screen may be unable to display the video.
In such a case, stop video playback, press the Fn+F7 keys to select the computer screen as the display output, and then press the Enter key. Then, restart video playback.