White horizontal line on screen

The screen diagnostic will help here:  hold the D key through powerup.  If that line shows on the screen self-tests (it likely will), the screen needs to be replaced.

At least it will leave you with an unbroken, intact screen - unlike a "flex" test, which could well crack an otherwise undamaged screen.

Welcome to the Dell Community @bella231 

Looks like a cold solder joint on the LCD.

Try performing a “Flex Test”

While the laptop is booted and the screen is on:

Grab the display at the upper left and right corners.

Then pull one side forward and push the other side backwards about 1/2" to 1"

Repeat back and forth. "Flex Test"

Is there any change in the display while flexing??

Best regards,

U2

From your unsubstantiated comment about a “Flex Test” damaging an LCD, it is evident that you have little or no experience working on laptop LCD’s.

Every laptop that we have tested over the last 20 years always ends with a “Flex Test”.

That would be well over one million laptops and out of my share of the million I have not cracked a single LCD performing a “Flex Test”

That does not include all the LCD’s that we test separately.

It is a quick and SAFE way to check for cold solder joints, which results in lines on an LCD.

Just because of your resentment for me does not justify your unsubstantiated comments.

Best regards and may you have a nice day,

Timothy J. Connors

Recommending that someone flex an LCD display is not wise.  It takes very little to crack a display panel these days, with very little in the way of give remaining in the very slim screen casings.

I am simply pointing out there's a better way than risking system damage.  Flexing won't fix the problem.  It's evident here, and the diagnostics are all one needs to verify that and find the solution.

It's not prudent to suggest a test that can cause damage that does not presently exist.  That's all I was pointing out.

If the system is out of warranty and that line is the entire issue, it's fairly easy to live with.  The same cannot be said for a cracked screen that arises as the result of a poorly thought out solution to the issue.

This could be an issue with the LCD. To isolate the issue follow below steps:

• Check if the vertical lines appear in BIOS screen (Restart the computer and tap F2 on Dell logo).
• Also restart the computer and check the display in Safe mode (Restart the computer and press F8 on Dell logo and select Safe mode)
• Run the diagnostics on the computer (Restart the computer by holding the” D” and power button and wait till the LCD test completes) and let me know the test result for LCD.

And remind us, please -- exactly what your flex test -- which, despite your luck in not breaking a screen -- yet, carries risk with it -- shows that the screen diagnostic does not?

A single-line fault will appear in operation and on a diagnostic screen, and means the screen needs to be replaced or lived with.

And bending the LCD is exactly what your procedure sounds like you asked.

The built-in diagnostics run from the screen itself - they do not pass data through the wiring harness from the system board, so they're just as effective as your "flex" test.

I know this is a bit old but I Had a thick vertical line on my Inspiron 15 5000 screen, not there when connected to the monitor, stays there when you press D and power button.  This suggests it is either the screen or the screen cable, I performed the gentle flex test and the vertical line disappeared.  Should I get a new screen or just replace the cable?

Thanks 

Wayneo

Im telling you, I made an account for this site just to thank you LOL

I jokingly did what you said even though I'm not on laptop but instead a 24" monitor, and to my surprise it worked