By using a laptop for a long time may affect its display with due to issues with one or more components in the display assembly. The formation of lines on-screen will be annoying very much and it is mainly caused by the video card, faulty cables or LCD screen.
1. First thing to do before you start to resolve the display problem is confirm the source of the problem by diagnosing it correctly. Connect the laptop to a projector and check the display and in case the external display is normal and display without not any lines, the problem probably is with the screen or it is associated with cabling. But in case the projector displays vertical lines, replacing the video card may solve the problem.
2. If there is a problem in LCD screen lines will seem to move, move orientation from vertical to horizontal or vice versa, grow fatter or thinner while adding pressure or move laptop around. If the display issue is caused by screen, replace the screen to solve the problem.
3. Another issue which may cause vertical lines on-screen is loose cable connections. For solving this problem undo the laptop’s display assembly and try to access the video cable. Find the long, flat cable and unplug it from both ends, then reconnect it strongly.