Laptop is beeping

Hi

My laptop is beeping while turning on and nothing is showing in display.

Beeping sequence is (beep-beep-beep-beep) (beep-beep-beep-beep) (beep-beep-beep-beep) ......

Please help me to identify the hardware failure which needs to be replaced.

Laptop Model- Inspiron 7520 (Windows 10)

Thanks