Macbook Pro late 2011 version won´t boot up
If you want to recover some data from you hard drive, I think that the best option is to start your Mac with CMD + R.
You'll need an external Hard Drive. From Utility choose "Disk Utility" and format the extenal HD in Mac OS X Extended (Journaled) with GUID Partition option.
After that, quit Disk Utility and Choose "Restore Mac OS X" from the main menu.
Complete the installation on the external HD and boot your Mac while pressing Option key.
Choose the External HD, and it will boot up with the new system where you can try to access to your data from Macintosh HD.

Otherwise unplug your internal HD and connect to your computer with a SATA-USB adapter.