The first step to PC Screen Lines on a computer monitor is to restart your computer and check the display cable for damage or loose connections. Update graphics drivers, change the screen resolution and refresh rate, and check if the monitor works with another device in order to eliminate the problem. If this problem occurs on several monitors, there is a problem with the hardware. If it happens only on one computer, however, it may be due to the graphics card or software. If the issue is chronic, a professional diagnosis and repair is suggested. Visit Devicesfixes to get more troubleshooting tips.