As many macbook core 2 duo owner, the backlight was broken because of the inverter cable.
Repair went pretty well, thanks to the handy and fit for the job tools coupled with very precise guides. After 2 hours of disassembling, cleaning 3 years of dust and re-assembling, the screen finally lighted up.
Don't use a recent magsafe adapter, it won't work and you could have the bad feeling of having definitely killed the macbook.
Also, before screwing the dvd drive, you should be able to slide a small piece of metal to align it with the screw hole and also lock the drive in the chassis.