Have you considered it might be the screen acting up on the Laptop? I'm not very familiar with laptops, but maybe the backlight is going out or something. Try pluging your Laptop into a TV via a HDMI cable and see if the problem continues on the TV. If it occurs, its a hardware issues on the Laptop. If not, then I'd consider your screen as a culprit.
Something else you could do is try checking out Event Viewer, its a good way to identify any serious issues that may be going on in the background without you even realizing
1. Right click your windows button and click Event Viewer.
2. Windows logs -> Then System.
3. Search for any vital errors or critical happening on your PC. Sometimes even the 'Information' tabs can have some evidence behind them.
Also, here's a thread I found online if this helps any - https://answers.microsoft.com/en-us/windows/forum/windows_7-desktop/thin-vertical-white-lines-on-monitor/095aec34-8fd8-404c-aea6-92cb498ef77b
Another one I found - http://h30434.www3.hp.com/t5/Notebook-Video-Display-and-Touch/Vertical-white-line-on-the-laptop-screen/td-p/3835370
Hope this helps somewhat, just throwing in some Troubleshooting advice.