How to Get Rid of Black Lines on a Monitor

While black lines on a monitor could be a signifier of a failing monitor, minor issues -- like a loose video cable or an outdated graphics driver -- could also be at fault. The video cable transfers data from the video card to the monitor; if the cable is loose, strange visual effects, like discoloration or lines on the screen, can appear. Outdated or corrupt video drivers can also alter video performance; updating the driver to the latest version can fix bugs that are causing problems with the monitor.

Check the connection between the monitor and the computer. Confirm that the VGA, DVI or HDMI cable is secured to the back of the screen and the PC. Tighten the thumbscrews on the cable connectors, if applicable.

Change the screen resolution. Go to "Start," then "Control Panel." Click "Adjust Screen Resolution." Click the drop-down menu next to "Resolution," then drag the slider to the "Recommended" setting.

Click "OK." If the black lines on the monitor persist, click the back button until you reach the main menu of the Control Panel. Click "Hardware and Sound." Click "Device Manager."

Expand "Display Adapters," then locate the device driver for the graphics card. If a "!" or "X" symbol is found next to the device, double-click the driver and check the "Device Status" field to determine the problem. Follow the instructions in the box to fix the driver.

Write down the name of the device driver. Go to the "Driver" tab, then write down the provider name, driver date and driver version. Go to the computer or graphics card manufacturer's website.

Go to the product page for the computer or graphics card model. Check the bulletin board, if available, for notifications regarding graphics-related issues. If a post on the bulletin board relates to your issue, read and follow the instructions in the post.

Navigate to the "Download" or "Drivers" page. Check the date and version of the most recent driver available. If the driver on the website is newer than the driver on your computer, download the driver to the PC. If the driver is not newer, return to "Device Manager," then right-click the display adapter. Click "Uninstall."

Double-click the updated driver to upgrade the display adapter. Follow the onscreen directions to complete the install.

Restart your computer when the process is complete. If the black lines are still on the screen, unplug the monitor from the PC and connect it to another computer. If the black lines disappear when the monitor is connected to another PC, you may need to replace the video card in your computer to fix the black lines.

Connect a new VGA, DVI or HDMI cable to the PC and monitor if the black lines are visible on the other computer. If replacing the video cable doesn't fix the black lines on the screen, the monitor may need to be replaced.