Monitor backlight comes on briefly, then blanks out

Question

I'm using a COMPAC PRESARIO laptop that's running WINDOWS XP.  I've had the system 7 years & had a couple viruses that were supposedly cleaned up, but it was done by someone else so I'm not sure of this. 
PROBLEM DESCRIPTION & CORRECTION EFFORTS TO DATE:
When the computer is turned on the COMPAC logo comes up, but soon blanks out, though not thoroughly on occasion, just goes real dark, with images faintly visible.  Unfortunately, the behavior is not consistent, sometimes not lighting at all, other times as previously described, not visible at all, or visible up to WINDOWS logo page, then blank.  If power is disconnected for 48 hours or better it will sometimes remain visible for a period of time, so long as it doesn't enter hibernation mode, though that trick hasn't worked recently; then the above problems repeat.  I have connected a COMPAC FS7600 monitor to it to see if it is indeed a monitor problem, but that also blanks out after WINDOWS logo displays, prior to reaching log-in stage, the monitor power button going from the green it has while visible to the amber that signals a disconnect (I think).  I've been forced to do hard shutdowns repeatedly, resulting in the "Windows encountered a problem with the last start-up" & have tried the "last working configuration" option, but that hasn't helped, so I'm at a loss on what to try next.
One of the answers here indicated the backlight could be replaced.  If so, how would I go about that if it comes to that?
I am a freelance illustrator & writer, whose work & income depend on a working system, so I'm currently unable to produce the products clients desire; as such, this problem is imperative to correct.  Any & all assistance will be greatly appreciated.  Thank you.

Answer 1

Hello @darenderer ,
Welcome to the HP Forums!
I understand you're having issues with the display on your notebook going blank.
If the issue persists on an external monitor chances are the issue is not hardware related, though when it goes dim and is barely visible that does sound like a bad backlight which is kind of strange.
We can test this by trying to load the BIOS. If the BIOS loads and displays properly this would tell us the hardware is OK. To access the BIOS tap F10 while the notebook boots up. If this is displaying OK you may need to restore the default BIOS settings which is usually done with F9 while in the BIOS. You should see the keyboard shortcut in the bottom right corner of the screen to confirm this shortcut.
If the BIOS does not display you could be looking at a hardware issue. The issue being intermittent like this might suggest a bad connection to the backlight or display. You can see how to remove and reconnect these connections in the Maintenance and Service guide available in the User Guides section of your products support page here: HP - Drivers & Downloads.
It would help to know which product and operating system you are using. For information on finding your product and model numbers click here: How Do I Find My Model Number or Product Number? To see which version of Windows you are using click here: Which Windows operating system am I running?
Let me know if this helps!
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