Lines that appear on your computer display can be caused by a variety of factors, including hardware problems, software problems, or connection problems. The following 7 - 22 Inch Monitors are the most likely situations and solutions:   Reconnect the video cable: Check that the video cable (such as HDMI, VGA, Display Port, etc.) is firmly connected to the computer and the monitor. Sometimes a loose or damaged cable can cause the lines to appear.   Replace the video cable: If the line persists, try replacing the video cable to make sure there is no problem with the cable itself.   Adjust the resolution and refresh rate: In the monitor display settings of your computer, try adjusting the screen resolution and refresh rate. Sometimes mismatched settings can cause lines to appear.   Check the pc monitor settings: Check if there are any configuration options in the monitor menu that can solve the line problem, such as clarity, sharpness, color, etc. settings.   Update the graphics card driver: Make sure the graphics card driver is the latest version. You can find the graphics card in Device Manager and try to update the driver.   Check for hardware failure: Lines may be a sign of a hardware problem with the monitor or graphics card. Try connecting another monitor to determine if the problem is associated with a specific monitor. If the problem persists with a different monitor, it may be a problem with the graphics card.   Check your computer hardware: If you suspect the lines are caused by a hardware problem, such as a graphics card failure or memory problem, try reinstalling or replacing the hardware.   Reduce electromagnetic interference: Keep your computer away from electronic devices and other objects that may cause interference to reduce the possibility of lines appearing.