If you're experiencing this issue with pc screen lines, it may be a problem with your display cable or that you have outdated graphics drivers, display refresh rate issues, or even a problem with your monitor panel itself. First, try reconnecting all of the cables, updating the GPU drivers, and then using the monitor with another computer. In the event that the lines are still on several devices, the monitor itself could be the problem. Running hardware diagnostics can also help determine whether the problem is with the display or the graphics card.