No Display after windows 7 Boot

[Selenium_Glow]

Hi everyone. I'm using a Dell Latitude E5420 with Core i5/HD3000/4GB/200GB(5400rpm).
The Display is a 14" 1600x900 display. This has Windows 7 64 bit professional pre installed.

Dell Care changed the display 3 days ago (replacing a badly flickering display with my current one).

Here is my problem, followed by what steps I've taken so far to figure out or fix the problem.

When I start my laptop, the screen turns on, shows the BIOS splash screen, and then followed by a prompt which requests an intranet username/password for the encrypted hard drive. Windows boots after this process. Here is where the problem starts. When I start my system normally, the laptop display turns off after Windows boots. However, when I connect a projector or some external display using the laptop's VGA port, the log-in screen appears on the secondary display, the laptop display still remains turned off.
- Windows and other functions work normally with the secondary display.
- Device manager shows only the secondary display. It does not show my laptop display in the device list.

It exhibits the same problem as stated above despite selecting any of the following options from the windows startup menu (Invoked by pressing F8 before boot):
- Debugging mode
- Start windows normally
- Boot logging mode
- Low resolution video (640x480) mode

However, the display turns on perfectly in safe mode.
In safe mode, the display works, but I'm not able to turn up or down the display brightness using the keyboard buttons. I also did not find my display device listed in the device manager when I was in safe mode.

I tried uninstalling, and then reinstalling display drivers, but the problem persisted. I also tried to recover previous settings and even tried to repair the windows partition. Recovering did not work and repairing the system doesn't show my installed windows as the drive is encrypted (I think).

I did some googling, and found this anandtech forum page, but it does not seem to provide me a solution that works for me.
http://forums.anandtech.com/showthread.php?t=2261847

Please help. I'm unable to figure out anything from what I've done so far.

Update: I ran the Pre Boot Assessment Utility (or Dell Diagnostic Utility as some may know). It passes all tests expect the "Notebook Panel" test. In this test, the laptop screen went completely blank, then kept beeping. After a lot of beeping, the display came back and gave me the following error message.

Fail PSA V4206 Error 2000:0333
Video - User provided no input for graphics test

I then connected the laptop to a external Panasonic TV, then ran the test. There were moving bands of colors followed by more moving bands of colors followed by a prompt which asked me if I saw any color bands or not. After like 15 seconds, it started making the same beeping sounds. I disconnected the external TV, and saw that the laptop display was still turned off. I pressed n on the keyboard. After a lot of more beeping noises, I got this message

Fail PSA v4206 Error 2000:0334
Video - User reported the patterns were not displayed

I now have a gut feeling that the display cable in the laptop is not connected properly or something. Ideas anyone?

 

[jolancer]

my guess... If the Dell Diagnostic Utility uses the same drivers as the OEM install, maybe its just a different Display device then what it originally came with so the Original driver no longer works. I dont no how old that laptop is but if its display wasn't obsolete i dont know why they would do that other then a Mistake? (however if the new display looks better then your old[if you can get it working] then i guess theres nothing to complain about)... I'd go maybe ask Dell which Display they put in so you can get the proper drivers for it, and if they say thats not the issue or it wouldn't fix your issue anyway... Then Basically id guess they Fuk'd up

EDIT: Im not going to edit my original paragraph tho it may make me look like an idiot i had a total brain fart, incase there is any validity to that if laptop displays do function differently... But I realized it didnt make any sense cause its the Onboard display adapter, not the monitor itself that is affected by the driver. So yea........ So if they didnt change out the Display Adapter with it? then i guess thy just fukd up

EDIT again: wait a min, that doesnt make sense either because your external port for the display adapter works fine.... Seems completely now like thy simply fukd sumthing up

 

[Steltek]

I now have a gut feeling that the display cable in the laptop is not connected properly or something. Ideas anyone?

I agree that something is amiss. You could open it up and take a look yourself (Dell's support documentation usually includes detailed teardown instructions for their laptops). However, as the machine has integrated graphics, this could also involve a motherboard fault. The best solution would be to make Dell fix it properly like they should have in the first place.

BTW, if the hard drive is encrypted, the documentation should tell you how to access it. If it doesn't, make sure they take care of that for you as well.

 

[Dahak]

sound like the repair is bad,

one possibility you could try although this is a long shot is when you have the 2nd display hooked up and logged into windows you could try hitting winkey+P and see if you can select computer only or duplicate and see if the laptop screen comes on.
also you could double check to see if there is a fn+key that does the same thing. ie on my hp laptop its fn+f4

its a long shot but who knows. it is odd that it will show up to the win boot but not after

 

[Ketchup]

You could try uninstalling the video driver and letting windows re-install them, preferably from Windows update.

If this doesn't work, I agree that it was probably a bad replacement. They may have replaced the display with a similar display that runs a lower resolution, but I think Windows would adapt to that for you.