Dell Inspiron 7520 : Screen starts flickering and gives 4 beaps on force shutdown and restart

I have Dell Inspiron 7520 3rd Gen 15s laptop.

This problem started recently. After working for a while on the laptop the screen starts flickering and stops responding. Only option to restart is to force shutdown the system. On again powering on the system it gives 4 beaps code. If you leave the system for some it restarts properly, windows is launched. But again after working for some time the screen starts flickering and the same issue.

Is there any place where I can upload a video showing the flicker problem.

Please tell me the probable isse and solution.