What causes vertical lines on computer monitor? Lines on computer screen can be triggered by various issues including outdated graphics card driver, defective ribbon cables, incorrect video cable connections, damage of the screen, etc. The lines can be vertical lines or horizontal lines that are in blue, white or multi-colored. Additionally, you may encounter another issue: your computer screen has lines running through it in Windows 10/8/7. When using your computer, you may find the monitor or computer screen isn’t working properly, for example, monitor not displaying a full screen that has been talked about in our previous post. My Computer Screen has Lines Running Through It What causes vertical lines on computer monitor? How to troubleshoot this issue? You can get the answers after reading this article. Today in this post from MiniTool, the topic – vertical lines on monitor will be discussed. Computer screen, like any component of a computer, may fail to work.