|The main issue would be defective RAM or RAM that is not seated correctly. |
The next one would be defective inverter, but you have a LED type LCD so that's not your problem.
Defective LCD, Defective or unseated LCD cable.
Next would be LCD control board fuse, Defective VRAM, Defective GPU, and at last the Defective Lid Switch.
And some other off the wall ones would be a dead CPU, a corrupted BIOS or a BIOS boot lock.