HP laptop has no video

Customer has a two year old HP Pavilion laptop running Vista, and reported that they could no longer see anything on the screen.  During testing, I CAN see the backlight come on while it's up and running, and the backlight turns off when Vista shuts down, but I never see any video at all.  However, if I have an external monitor connected, I see everything like normal.

I can't see anything in the BIOS that would affect this, and I'm assuming that an incorrect function key setting would surely not keep it from showing any video at all, such as during boot up.

HP wants $50 just to talk to me.  I'm assuming this is a hopeless case, short of having the customer spend megabucks on a repair.  So, before spending money with HP, I'm hoping to get some guidance here on a likely cause and/or approx. costs to repair--and whether that's even worth doing.  TIA
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Jerry MillerConnect With a Mentor Commented:
You don't even get the POST messages during boot?  It sounds like either the contrast or brightness is not functioning normally. Verify the neither one is set all the way down to the darkest setting.

If you get the POST messages but nothing in Vista, verify that the resolution setting is supported for the video driver. Since you can connect an external monitor, you can see the resolution settings and make appropriate changes.

One hardware thing that you can check. Most laptop screens have an inverter board that connects the LCD to the mother board. Here is a way to verify that the inverter is good. This will narrow it down to the LCD itself. But I think that the inverter is probably your culprit.

nobusConnect With a Mentor Commented:
web_trackerConnect With a Mentor Commented:
This sounds like a typical backlight problem, especially if  your system works fine using an external monitor. When the OS boots up, try shining a flash light on the lcd screen to see if you can see any video, if you can then it is definitely a backlight problem. This part is usually quite cheap and fairly easy to replace. You would not have to replace the lcd screen. If it does not seem to be a backlight problem then it could be a bad signal cable going to the lcd screen or the lcd screen itself.
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edbedbConnect With a Mentor Commented:
Replacing the LCD screen will fix the problem. If you shop around you should be able to get it repaired for $150 or less.
you can also test with an external monitor !
Grant1842Connect With a Mentor Commented:
Here is some info that I wrote it may help you.
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