Why is my unreal engine flashing after a while

Hello guys so my unreal engine is flashing after a while like in this video i reinstalled windows and reinstalled the engine
but i cant fix it
Here is the video : Unreal engine flashing

This is a known NVIDIA driver bug. I’m afraid I can’t point you at the solution, but downgrading to ‘studio’ drivers, or searching around the NVIDIA ( or Epic ) site will provide the solution.