Why my laptop screen wont turn on?

Hello, my Toshiba Satellite L305D-S5893 was working fine last night but today the screen is dead.

The laptop doesn't gave me any sing or symptom of malfunction at all, it seems to be on, has lights on battery, charger and cd drive. The fan, cd drive and hard disk drive worked but the screen is dead, no beeps or any unusual sound.

Laptop turns on with battery power and AC power, i removed the RAM memory and connected an external display but nothing changed, i tried to boot from cd but nothing worked, the screen is just dead.

I'm stuck right now, i don't know what is the problem or how to diagnostic it, obviously i don't know how to fix it.

Any information, reference or advice will be appreciated. THANK YOU in advice for your time and attention.

P.S. Sorry for my broken english.