Is on but black screen

You may have a defective CCFL backlight, it may have the following symptom: Screen flashes on and off or displays reddish pink hue. Picture stays on in red and slowly be come normal. Picture flickering with dim display or appear black. Picture flickers on and off. All these symptoms indicate that the LCD backlight lamp (CCFL Lamp) has reached the end of the life and all you need to do is replace the CCFL lamp.
To determine if the video card or the LCD is faulty, connect an external monitor to your laptop and power the monitor up first then the laptop, if you see the normal Windows images then the video card and laptop is OK and the problem is definitely the backlight. Dim image and/or dark display on the laptop's LCD screen indicates a faulty LCD backlight. It could be the inverter that supplies high voltage to the CCFL lamp or it is the CCLF lamp is nearly burnt out, this is the most likely case.
The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
Check out LCD Parts for service, parts, and DIY info Use this link to their WEB site :-
www.lcdparts.net