How do I Fix the Horizontal and Vertical Lines on a Dell Monitor Image?

By Nina Nixon

Updated September 28, 2017

i Hemera Technologies/ Images

There are two common reasons why a Dell or other type of monitor will display horizontal or vertical lines. If you have recently upgraded your computer and have a desktop, your monitor may not be compatible with the new system as is. Also, incorrect video cables and port connections can cause a monitor's display to be unclear. If your laptop is affected, you can run a Pre-boot System Assessment (PSA) and perform an LCD Built-in Self Test. If your computer has a CRT monitor for a desktop, looking at cables and connections is a good place to start.

LCD Laptop Monitor Diagnostics

Turn off your computer and then hold the keyboard's "FN" key down while you press the "Power" button for two seconds. (PSA Diagnostics will start.)

Press the "N" (No) key to start the LCD BIST (Built-in Self Test). Display issues such as horizontal and vertical lines and other distortions should appear if they are found. Screens in full color will display consecutively along and the computer will emit a beeping sound during the diagnostic.

Press the "Y"(Yes) key on the keyboard after the error message appears if your horizontal or vertical lines were displayed; otherwise, press "N" to end the PSA Diagnostics and then go to the last step in the LCD BIST. If you still experience problems with your Dell Monitor display, contact Dell Technical Support. The link is available in Resources.

Dell CRT Desktop Monitor Troubleshooting

Check the power cable monitor to the AC outlet for a secure connection. (Desktop monitors have a separate power connection.)

Check that the monitor is securely connected to the correct display port connector, whether it is a Display Port, Digital Video interface (DVI), Video Graphics Array (VGA) or High-Definition Multimedia Interface (HDMI).

Turn on the computer and then click "Start." If your computer was already on, close all programs and then click "Start."

Click "Control Panel," then click "Appearance and Personalization" in the Control Panel window.

Click "Display," then "Calibrate Color" and follow the steps of the wizard to complete color depth adjustments. If you still see horizontal or vertical lines on your Dell monitor display, contact Dell Technical Support. The link is available in Resources.


Register your Dell monitor and sign up to receive product update notifications or check the Dell support website for updated drivers for your monitor either monthly or quarterly.


Multiple video signals can cause monitor display problems, therefore, if you have more than one option to connect, be sure to use only one of the ports on your computer.