I have a hp dv6000 laptop, it dosn't move much and doesn't have much wear and tear but the screen seems to have gone dead. It remains lit black, but doesn't display anything except for a few seconds during the windows loading screen or just before the desktop loads, where it displays normally, though it flickers very slightly, then goes right back to lit black.

I don't move it around so i figured i could just turn it into my desktop, but when i plug in a lcd moniter, and it works fine during the boot sequence, into the windows loading screen then gives me a no signal message on the moniter then turns to black. Unplugging and replugging the monitor doesn't return any image.

Booting in safe mode does not remedy this problem BUT booting in VGA mode does. When i boot in vga mode it loads up at low resolution just fine, though if i go into the display settings and change any setting that would cause the video to reset ie switch resolution then click apply, monitor turns black just like during regular bootup. This includes when i try to disable the default monitor. Note that during this vga process the regular laptop screen still does not display, only the external monitor.

The laptop continues to run properly despite no image, as i can shut it down and restart it through keyboard commands.

Please note before responding that the bios for this laptop contains no options for default video device, the only video options are for changing the memory buffer, which has no effect.

Any solutions? Could this actually be a graphics card failure? I am very experienced with pc's hardware and software, and have done a fair amount of work on laptops, though nothing concerning screen replacement before.
Thanks in advance.

note: this laptop originally had the mobo die, as a result of a production fault, and was serviced for free a year after it died since the problem was so common. Since then it has had no out of the ordinary issues, except slow network resolving which i can't imagine any correlation. No settings or drivers or updates were being done anywhere near the time of this screen failure, and i keep antivirus and antimalware apps running and up to date.

Have you tried reinstalling the video or chipset drivers from HP's support site. I know this can be difficult in low resolution

Update:
This problem is related to a dv6000 motherboard defect. They have a 2 year extended warantee for this mobo, which i used when it fully died the first time, but now i'm out of warrantee. Apperantly the board overheats and this causes random parts to fry, this time it was the onboard nvidia go video card.

So a three year old laptop, and is now onto its second motherboard replacement, good job hp. They offered a 50% discount on services, so $277, but i just ordered a new motherboard for $72 and will install it myself. Will update again afterwards