If you notice pc screen red lines, it may indicate a graphics card issue, overheating GPU, or a damaged display panel. The first step is to restart the system and update graphics drivers. You can also look at whether the lines are present or not when you are using a different monitor. In case they are lost in another screen, the monitor panel may be malfunctioning. Nevertheless, when the red lines persist in more than one display, then it is more probable that the issue is with the graphics card.