Four thin horizontal lines have gradually appeared along the top edge of my HP EliteBook 840 G6 display. The first showed up about seven months ago, and a fourth line appeared today. I noticed each one after a Windows update, so I'm wondering whether a software or driver problem could be causing this. Is there a way to fix it without replacing the screen?
1 Answer
Check whether the lines are visible in the UEFI/BIOS screen or during the built-in display diagnostics. Since they also appear there, Windows and its drivers aren’t the cause. The pattern points to a failing LCD panel or its internal connections, so replacing the display assembly is probably the practical fix. You can also test with an external monitor: if that looks normal, it further confirms the laptop’s built-in screen is failing.

The same lines are visible on the BIOS screen, so it looks like the problem is hardware-related rather than something caused by Windows.