Gray screen problem in Dell Latitude E6540 when I watch an video

Gray screen problem in Dell Latitude E6540

The computer functions normally

But when I want to watch a movie or a video either on my hard disk or on the internet ... the gray screen appears

{Note: if i minimize the video box for example in “vlc” the problem does not show  .. but its appear on plein ecran mode when the video fills the computer screen}

The problem rarely appears immediately after the dell logo when the computer is turned on

To get rid of the problem I have to close the screen and open it…  and so on every appearance

Here are some steps i've taken to try to diagnose the problem:

1 I connected an external monitor once with the HDMI cable and once with the VGA cable when the video started after a short time .. The problem appeared in the computer screen only  and the external screen is good .. the video shows normal

2 i entered the safe mode and the problem still exists

3 I try to format the  computer with Windows 7/10 and the problem still exists

4 I updated the drivers of the Intel and AMD graphics card and the problem still exists even without drivers

This is a video and illustrations

https://www.youtube.com/watch?v=sH_GAil-...

I apologize for the language errors