green lines

Green lines on a Windows PC screen often indicate graphics hardware or driver issues, especially when they appear during video playback but not in other tasks. Users have reported green and yellow lines in Windows 7 when using media players like WMP, GOM Player, or MPC HC, while online videos play fine. This suggests a problem with video codecs, graphics drivers, or the GPU itself. In some cases, green or red lines appear only when a video is opened, disappearing when the player is closed. Other symptoms include colorful blocks, vertical bands, or diagonal dotted lines, sometimes leading to safe mode. Troubleshooting steps include updating or reinstalling graphics drivers, checking for overheating, testing with different cables (DVI, HDMI, VGA), and verifying the monitor or projector is not at fault.