First good test is to do what Tmagic650 suggests. Plug in an external monitor. If it runs, the problem is the backlight board.
The screen inverter has been failing early in plenty of Compaq Presario V3000 series. - Laptop boots but screen blacks out. User can sometimes a very faint image on screen... sometimes notn. Sometimes see it better with an LED flashlight. May even come back sometimes.
See if you can briefly see this backlight turn on when you tap rapidly on the lid close switch.
On others the screen remains dark and the backlight never turns on, but you can still detect a dark image on the LCD.
You may even hear noises from the base of the screen where this inverter board resides on a cable attached to the internal screen base frame.
If so, the part can be found on eBay for less than $20, or at HP for $59, but it is damnably difficult to replace. There are about 24 screws, and most are hidden by screw hole covers.
Still, using a very high quality philip screwdriver and a sharp tool to lift off the screw covers, you can replace it in less than an hour.
Repair shops in the USA charge about $150
but yes, agree, symptoms for it's death are quite unusual.
