I have had this once, but it was after a lightning strike on my previous MacBook. All I did was reset the pram, and the screen came up again, although the strike had caused it to flicker. Insurance company sorted that one out. I would still try the pram reset though,
Hold down apple
alt+pr as you turn on. When you hear the third chime, let go and see if it re-boots successfully.
Karn.