Why Are There Lines on My Screen? (Vertical and Horizontal)

Lines across a screen look alarming, but they are rarely random. Their direction, their color, whether they move, and whether they show up in a screenshot together point to one of three places: the signal coming in, the graphics hardware producing it, or the panel itself. Ten minutes of testing usually tells you which — and whether a repair is worth paying for.

First: is it the screen or the signal?

Three quick checks split the problem in half before you go any further.

1. Take a screenshot and look at it on another device. A screenshot captures the image the computer produced before it was sent to the display. If the lines are in the screenshot, the panel is innocent — it's software or the graphics card.
2. Try another source or another screen. Plug a different laptop or console into the monitor, or connect your computer to a TV. Lines that follow the computer are a graphics or cable problem; lines that stay with the screen belong to the panel.
3. Open the monitor's own menu. The on-screen menu is drawn by the monitor itself, not by your computer. If the lines cut straight through the menu, the fault is inside the monitor. On a laptop, the nearest equivalent is the boot logo or BIOS screen: lines there appear before any driver has loaded.

For a deeper walk-through of the signal side, see Is It the Screen or the Graphics Card?.

What the lines are telling you

• One thin vertical line, always the same color, never moving. A single column of pixels has lost its drive signal or is stuck on. The columns are fed by driver chips bonded along the top or bottom edge of the panel; when one of those bonds cracks or lifts, its column freezes. This is a panel fault, and it is permanent.
• A cluster or band of vertical lines, often colored. A wider failure of the same kind — several columns from one driver at once — or a poor connection between the panel and its controller board. If the lines change when you press gently on the bezel along the top or bottom edge, or flex a laptop lid, a connection is loose.
• Horizontal lines. Rows are driven from the sides of the panel, so a fixed horizontal line points to a row driver or its connection. Thin horizontal lines that flicker, crawl, or come and go are more often interference or a marginal cable.
• Lines that move, shimmer, or change with what's on screen. That is almost always the signal: a loose or under-spec cable, a failing port, a driver problem, or a graphics card that is overheating.
• Lines only in games or one app, often with colored blocks or sparkles. Classic graphics card artifacting — usually heat, an overclock, or failing video memory.
• Lines that appeared after a drop or a knock, often with a dark blot nearby. Physical damage to the panel — see Cracked Screen: Just the Glass, or the Display Too?.
• Laptop lines that change as you open and close the lid. The display cable runs through the hinge and wears with every opening. It's one of the most common laptop faults, and replacing the cable is far cheaper than replacing the screen.

Tests to run

1. Show a White Screen full-screen. Dead columns show up as dark lines, and lines that are faint on a busy desktop become obvious.
2. Show a Black Screen. Columns that are stuck on glow against black.
3. Step through red, green and blue in the Color Test. A line visible on only one color has lost a single sub-pixel channel; a line that looks the same on every color is a dead or stuck column.
4. Check whether the line runs the full height or width of the panel. A line that stops partway, or ends in a blot, suggests physical damage rather than a driver fault.
5. Try a different cable and a different port, and drop to a lower resolution or refresh rate for a minute. If the lines vanish, the old cable wasn't carrying the full signal reliably.

What you can fix yourself

• Cables and ports. Reseat both ends, try a certified cable that matches your resolution and refresh rate, and avoid cheap adapters. A cable that works at 60Hz can fail at 144Hz.
• Drivers. Update the graphics driver — or, if the lines started right after an update, roll it back.
• Heat and overclocks. Remove any graphics card overclock, clean out the dust, and watch temperatures under load. If the artifacts stop when the card is cool, the card is the problem.
• Laptop hinge cables. A repair shop can usually swap the display cable for a fraction of the cost of a new panel.

What you can't

A failed column or row driver, a lifted bond along the panel's edge, or a cracked panel means a panel replacement. You'll find videos recommending heating the edge of the screen, pressing on it, or wedging folded paper under the bezel. These occasionally make a line disappear for a while by pushing a cracked bond back into contact, and they just as often make things worse. Don't try them on a screen you might still return.

Warranty and returns

Unlike a single dead pixel, a line across the screen is a clear defect, and manufacturers almost always treat it as one — as long as there's no sign of impact. Photograph it on a white and a black screen, note the date, and contact the retailer while the return window is still open. If you've spotted a few dead pixels as well, Dead Pixel Warranty Policies, Explained covers how manufacturers count them.

And if the lines vanished the moment you tapped the screen, someone may simply have been running the Fake Broken Screen prank on you.