Black screen only during boot, afterwards image displayed ok

Hello.

I have a strange problem with my Inspiron 1720.

During boot (bios and windows) the screen remains black (no image is displayed, but the screen is lighted); after windows loads, the image appears on screen (everything is displayed; the display works without any problem). Other important remarks:

- NVIDIA Control Panel says "Laptop Display (disconnected)"
- if I connect an external monitor to vga port, the image on laptop display gets black and that monitor becomes the only display recognized by the system; if I pull out the vga cable, the system doen't recognize laptop's display and a reboot is necessary for it to work again
- if I power on the laptop with an external monitor connected, everything appears on that monitor (bios load, windows load etc.) and the laptop's display remains black
- the system doesn't detect anymore if the lid is closed or not
- when windows turns off the display, only the image dissapears, the display is lighted continuously
- dell diagnostics doesn't find any problem

If anyone have an idea of what's going on with the system, please help me. Thank you.

 

Maybe a new monitor cable?

Or the switch that turns the monitor off when the lid is closed is messed up?

 

I thought of that; the thing is, shouldn't I have and other simptoms with the display if the cable is (suddenly) bad?

I don't have such a switch; I guess it's based on magnets.

 

Have you tried to reinstall/update the graphicsdriver?
It could be a setting issue, where the comp has become 'confused' of what screen is the primary.

I'd try to reinstall the drivers, and reboot, to see if it had any effect. -Without any external screen connected.

 

Tried it, with no luck. The thing is it cannot be that because I don't have image before windows loads (with its drivers), so the OS can't be the source of my problem

 

Good point. It is indeed weird that there is no picture during POST.
If I understand correctly, hitting the setup-button to enter BIOS changes nothing, still black screen while in setup? Mighty strange.
It is the same symptoms I got on an old 510M, using a relic of a projector as screen. Somehow the computer got weirded out by my untimely use of 'Fn'-'F8'. -have you tried playing around with the 'Fn'-'F8' buttons? -the CRT/LCD option? That can create some windows/drivers/screen-priority havok.

 

How about clearing the CMOS?My old e1505 wasnt to easy to get to but....

If you can get to your motherboard battery take it out for 1 minute put it back in and boot.

Before you do make sure you unplug the AC cord and remove your main battery

 

Yes, still black.

Tried that also, no luck

 

Done that, still the same

 

Uhrrmm. BIOS update?!
This is weird indeed. What BIOS version are you running? A09?
Has it been like this for ever. Did the black screen appear as of lately?

 

I have A09...I see it's the latest...did the update 2 years ago

 

Do you have any other mohickeys connected to the computer, while booting?? -Anything. USB, external drives, anything.

I have an HP Ipaq 214 pda, I scratched my head alot, until I figured out that the computer won't boot at all, if it is connected to the USB(!) Silly thing.

 

Maybe reflash the BIOS.

I doubt it but its worth a shot.

 

I am starting to believe the same. There seems to be something funky going on right there. If the BIOS is updated/reupdated, the BIOS would be reset, and everything should be doing fine.
Since the graphics are being rendered as usual (after startup) it doesn't really imply that there is something wrong with the vbios.
There could(?) be something iffy with the BIOS, although I cannot figure out exactly why it lets thing go as normal after POST/winload

Are you using VGA-cable, HDMI or that third thing? (-name forgotten due to intake of beer, sorry)
Could it be that the screen doesn't activate until after Windows is loaded. Oh, sorry, laptop *note to self...*
Just had to ask... ...it is that square peg in a round hole-thing that drives me to ask stupid questions from quite experiensed users. -It makes me unpopular sometimes.