Can't unlock my MacBook Pro. Recently, I've changed my password, now I can't access anything. Please help!!!

Question

I Have a MacBook Pro 13, which I bought in 2010. I'm not really sure which version of operating system I do have, because I haven't updated it for a long time. I've changed my password recently and now I can't unlock it. It just jiggles and says that password is wrong. Then it asks the security question, but even doesn't work. I'm pretty sure that I'm typing everything correct, but it's not working. I took it to the service store, they couldn't do anything. Please help me to unlock it.

Answer 1

A login password for the computer is not the password used for your Apple ID. To change a forgotten or lost password:
Forgot Your Account Password
For Lion, Mountain Lion, or Mavericks
    Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
     When the menubar appears select Terminal from the Utilities menu.
     Enter resetpassword at the prompt and press RETURN. Follow
     instructions in the dialog window that will appear.
     Or see:
       Reset a Mac OS X 10.7 Lion Password
       OS X Mountain Lion- Reset a login password,
       OS X Mavericks- Solve password problems,
       OS X Lion- Apple ID can be used to reset your user account password.
For Snow Leopard and earlier with installer DVD
     Mac OS X 10.6- If you forget your administrator password,
     OS X- Changing or resetting an account password (Snow Leopard and earlier).
For Snow Leopard and earlier without installer DVD
    How to reset your Mac OS X password without an installer disc | MacYourself
    Reset OS X Password Without an OS X CD — Tech News and Analysis
    How To Create A New Administrator Account - Hack Mac