My macbook pro is asking for a pin

Did you try searching before asking? MacBook Pro 13 Unibody Early 2011 Battery Replacement

This sounds like a PGP lock. You'll need the pin or a boot disk to wipe the drive and re-install osx

Hello:
1) What model and what year is your Macbook Pro?

2) What country are you in?

3) Is your Macbook still under warranty? That is, can you call Apple or send it to Apple for repair if you have to? Because on some Macbook Pros, only Apple can reset the EFI PIN

The Mac is locked and has it say you need a code to open, so if you know the person who gift you the Mac ask for the code if no the only remedy is to re-load the system but you will need the the copy of the O.S.

http://systemlockpincodemac.123website.nl/
http://systemlockpincodemac.123website.nl/

http://systemlockpincodemac.123website.nl/

I think this is what you are asking?
If not can you clairify?
What o.s, what kind of laptop?

http://www.ihackintosh.com/2009/05/how-to-hack-the-user-password-in-mac-os-x-without-an-os-x-cd/

You can reset your password with the OS disc. Reboot using the disc and choose Reset Password from the menu bar.

You need a firewire cable.
Most likely a 4 to 6 pin unit unless the Mac has an 800 port, then use a 4 to 9 pin.

The problem lies in your cable!

The new macbook pro still uses firewire and will be compatable with your drive. It just uses a 4-pin instead of a 6-pin connector. You can get an adapter or new cable that goes from 6 to 4-pins.

They did take away firewire from the new line of plain macbooks though (shakes fist at steve jobs)

I've experienced it, but after a while the problem dissappeared again.....