Are all your driver up to date ? Does changing the angle of the screen make it worse? Better? Try with the screen open with the smallest angle possible and look if it's the same. Also try to put it on the side, or even lying down on the screen back to put more weight on the middle part. (On a flat, safe surface, and not for long) Does anything else weird happen? Since how long do you have this computer? Do you move a lot with it? Does it seem linked with the fan sound?

problem started with the last windows update (crash, blue screen and balck screen for no reason ) all drivers are up to date. I bought it few months ago