Hi -- thanks.
When I remove the mouse and use the trackpad the problem persists. A crosshair mouse cursor on the left edge of the screen does cause some lines (and yes, these particular lines disappear when I move the cursor away from the left edge of the screen), but these lines appear in many other different pixel configurations independently of the mouse, as the image here shows: http://imgur.com/a/PRMJ1
Overall it's not related to the mouse.
I vaguely hope that some monitor firmware update might solve the problem (some faulty visual algorithms processing certain pixel configurations might screw up the vertical sync, which could cause the flickering lines), but I am not sure if these firmware updates even exist.
Short of that, it appears my only hope is a faulty or improperly plugged internal DVI/HDMI cable, which I could conceivably change or plug in more firmly (opening up the laptop is complicated but feasible): if the screen hardware itself is kaputt, then yes -- trying to change it might not be worth it.
Edited by GakHG, 19 March 2017 - 07:33 PM.