Q: Macbook pro

What model MacBook?

Maybe

MacBook Pro (15-inch, Mid 2010) intermittent black screen or loss of video Quality Program has ended - Apple Support

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

Otherwise:

- Try resetting the SMC and NVRAM/PRAM

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

About NVRAM and PRAM       

- Try starting in Safe Mode

OS X: What is Safe Boot, Safe Mode?

- Boot to Recovery and repair the startup disk

OS X: About OS X Recovery - Apple Support

- If it is repairable reinstall the OSX

How to reinstall OS X on your Mac - Apple Support

- If you do not have a backup use disk utility to restore the internal disk to an external disk so you can try to recover data.

Then format the startup disk and do a fresh install of OSX

Your Mac is one of the models covered by:

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

I would contact Apple as described in the article.

You can also make an appointment at the Genius Bar of an Apple store. If not that problem they can help too,

  Apple Retail Store - Genius Bar