The projector can be plugged in and turned on, the laptop refuses to send any image to the projector.
Laptops usually have a function key to toggle the display to the projector:
To switch to the projector, it is usually necessary to press the keys Fn + F10 (or other function key depending on the laptop).

By pressing these keys, the display of the laptop switches successively between the following modes:

  1. Screen only,
  2. VGA output only (video projector),
  3. VGA output + Screen.
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It is recommended to switch to have the screen only (black screen, to be sure that the video is sent to the projector), then make the necessary settings on the projector (choice of source) and finally to display on the VGA output and the screen when everything works.

If pressing the function keys does not work:
check that the projector is correctly connected.
If necessary, restart the computer with the projector connected and switched on.