MB boots with chime and black screen then on led fades

Hi all

I have had my macbook since 2006, think it is the first model with the intel core due 1.83mhz

Some time ago it went all dead, i came to the result after some troubleshooting, that the harddrive by some reason was faulty, i tried to replace it but it still wouldn't work, then i tried to take a flash and light up teh back of the screen through the apple logo, here i could see something on the screen so i assume the LCD is not broken, I have looked a lot for a solution and is in a fuss weather i need to do an expensive logic board replacement or if the problem is elsewhere.

I have at some point a couple eof years ago replaced the original drive that was roumored to be faulty with another drive (think it was a seagate.)

I have reset the computer in all possible aspectse, it boots with the bong then the on led fades and nothing else happens. Almost the opposite way as to when i usually closed the screen while the computer was on, before the problem really arose i had problems waking up the computer when i opned up the screen.

Regards

Mark Larsen