The laptop screen shows vertical dotted lines. The dots are red and moving up and down. The external monitor connected to the laptop either has garbled image or shows same dotted lines.

Possible cause:

1. Failed memory.
2. Failed video card.

Possible troubleshooting steps and repair solution:

If the problem appears on both the laptop screen and external monitor, it’s not related to the laptop LCD screen or video cable. Most likely the problem is related to the faulty memory module or video card.

Download Memtest86+ (google it) and test laptop memory. If the laptop has two memory modules installed, remove them one by one and test separately. If one of the memory modules fails test, move it to another slot and test again, just to confirm that it’s bad module, not the memory slot. Replace the failed memory module with a new one if needed.

If laptop memory passes test a few times, most likely there is a problem with the video card. In most laptops the video card is a part of the motherboard and cannot be removed and replaced separately. If the video card fails, you’ll have to replace the entire motherboard.

The laptop has a few very thin colorful lines on the screen running from top to bottom. These lines are vertical and spread with irregular intervals. Lines appear on the screen even on the BIOS level.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

This is LCD screen related failure. Most likely there is a problem with the LCD controler board on the screen.

In this case you’ll have to replace the LCD screen or use the laptop as is. The screen cannot be repaired, it has to be replaced.

There are horizontal flashing lines running across the laptop screen. The laptop starts fine and you still can see the picture, but there are flashing lines running across a part of the image.

Possible cause:

1. Video card failure.
2. Bad connection between video cable and LCD screen.
3. Bad LCD screen.
4. Faulty video cable.

Possible troubleshooting steps and repair solution:

1. First of all, test the laptop video output on the external monitor. If you see same flashing lines running through the image on the external monitor, you have a problem with the video card. If flashing lines appear only on the laptop screen, the failure is not related to the video card.

2. Just in case, try re-seating the video cable connectors on the motherboard/video card and maybe the back of the LCD screen. It’ s not likely but possible that connection is loose and reconnecting the cable will fix the flashing lines.

3. If re-seating the cable connectors doesn’t help, most likely you have a faulty LCD screen. The LCD screen has to be replaced.

4. If replacing the screen doesn’t help, try replacing the video cable. It’s very unlikely that this problem is related to the video cable but there is a slight possibility of that.

A green vertical line appears on the laptop screen. If the monitor is slightly tapped or moved the line sometimes disappears.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

If you have a single vertical line on the laptop screen running from top to bottom, this is LCD screen related failure.

Most likely there is a faulty solder joint somewhere on the screen controller board, and tapping or moving the monitor temporarily “fixes” the problem, making the screen work properly for a while.

This problem cannot be repaired at home. You have to replace the laptop screen with a new one or use it as is with the line on it.

A wide vertical stripe blocks image on the laptop screen. Everything works fine on the left and right sides from the stripe.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

This is laptop screen failure. The LCD screen cannot be repaired, it has to be replaced with a new one.

If the stripe blocks significant part of the image on screen and makes it unusable, you can set the laptop to output video on the external monitor and use it until the LCD screen is replaced.

The laptop screen has a transparent stripe running from top to bottom. You still can use the icons on the desktop located behind the transparent stripe.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

This problem is related to the laptop LCD screen. The LCD screen cannot be repaired and the transparent stripe cannot be removed. You will have to replace the LCD screen or use it as is.

Horizontal lines appear on the laptop screen when the laptop display panel is moved. Video on the external monitor works fine even when you move the laptop display. This problem appears only on the laptop screen.

Possible cause:

1. Poor connection between video cable and LCD screen.
2. Bad video cable.
3. LCD screen failure.

Possible troubleshooting steps and repair solution:

If horizontal lines appear only on the laptop screen, the problem is somewhere inside the laptop display panel.

1. Could be poor connection between the video cable and LCD screen. Reconnecting the video cable connection on the back of the LCD screen can fix the problem. Make sure the video cable is plugged correctly, all the way into the connector.

2. Could be damaged or defective video cable. Try replacing the video cable with a new one.

3. If reconnecting or replacing the video cable doesn’t fix the problem, most likely this is the LCD screen failure. Replace the LCD screen.

When you start the laptop, there are lines running though the manufacturer’s logo. Windows will not load. Same lines running through the logo appear on the external monitor.

Possible cause:

Video card failure.

Possible troubleshooting steps and repair solution:

When you have lines running through the laptop logo on both internal and external screens, most likely the laptop has a failed video card.

If the video card is a discrete module, you can try reseating the card. Unplug it from the motherboard and plug back in. It’s possible this failure occurs because of bad connection between the video card and motherboard. If reconnecting the card doesn’t help, you’ll have to replace the video card.

In most laptops the video card is integrated into the motherboard and cannot be removed and replaced separately. If the video card fails, you’ll have to replace the whole motherboard.

The laptop has a transparent vertical stripe on the screen running from top to bottom. You still can see the image behind the stripe, but it’s not as bright as image on the rest of the screen.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

This is the LCD screen related failure. This problem cannot be repaired at home. If you have a transparent vertical stripe on the screen, you’ll have to replace it with a new LCD screen or use as is.

Alternatively, you can use your laptop with an external monitor. The external picture will not have this stripe.

The laptop screen has horizontal white stripe. The stripe appears as soon as the laptop is turned on and runs even on the initial screen with manufacturer’s logo. When the laptop is booted to the desktop, the image behind the stripe is not visible. The rest of the screen works fine.
In some cases the stripe can be transparent.

Possible cause:

LCD screen failure.

Possible troubleshooting steps and repair solution:

Most likely this problem is related to the laptop LCD screen failure. The screen cannot be repaired and has to be replaced.
You can confirm the LCD screen failure by testing the laptop with an external monitor. The external picture should look normal, without any stripe.