Q: Backlight turns on bit no image on Mac Book pro

What specific Mac? maybe:

http://www.apple.com/support/macbookpro-videoissues/

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

  About NVRAM and PRAM

- Try connecting an external monitor to see if that works

- If still problem, make an appointment at the Genius Bar of an Apple store since it appears you have a hardware problem.

  Apple Retail Store - Genius Bar

This is the Mac Pro desktop forum. I requested your post be moved to the MacBook Pro laptop forum.