will the laptop power on? if so does it stay on or does it shut down? if it stays on is the problem just the display is dim? if this is the case it could also be the display dimmer switch which is connected to the motherboard? if its not that then it could be the motherboard itself, i was able to purchase a board on line from notebookparts.com for $200, replacing tha is no easy task if you've never done it before, i had a shop do mine while i watched and believe me it is not as easy as taking apart a pc. if you know any one whos ever worked on laptops ask for their help before trying it your self.