Master reset and reinstall OS X a Macbook Pro 2011 15 in

[lateefahbailey]

After trying to reset and reinstall OS on MacBook Pro now I have a lock sign how to gain access back into my MacBook

 

[BadAsAl]

If it looks like the "MacBook Firmware Lock" (Google it for what it looks like) then unless you know the password or you can prove to the Apple store that you own that Mac via a receipt you are out of luck.

 

[BadAsAl]

Here are the various boot screens explained: https://support.apple.com/en-us/HT204156