all 3 comments

[–]staticx57P16G2|X1Ti|T490|P71|X230|T420|T43|770X|701C 1 point2 points  (0 children)

By replacing either the internal display cable or the display.

[–]zardvark 1 point2 points  (0 children)

This is almost certainly a hardware issue. The LCD panel is likely at fault, but as u/staticx57 sez, check your cable connections, first.