How I can recover my user admin password of my computer?

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.

You can't recover the password, but you can reset it.

If the user account is associated with an Apple ID, and you know the Apple ID password, then maybe theApple ID can be used to reset your user account password. In OS X 10.10 and later, this option also works with FileVault, but only if you enabled it when you activated FileVault. It's not retroactive. Otherwise, see below.

Note: If you've activated FileVault, this procedure doesn't apply. Follow instead these instructions.

Start up in Recovery mode. When the OS X Utilities window appears, select

Utilities ▹ Terminal

from the menu bar at the top of the screen—not from any of the items in the OS X Utilities window.

In the window that opens, type this:

resetp

Press the tab key. The partial command you typed will automatically be completed to this:

resetpassword

Press return. A Reset Password window opens. Close the Terminal window to get it out of the way.

Select the startup volume ("Macintosh HD," unless you gave it a different name) if not already selected. You won't be able to do this if FileVault is active.

Select your username from the menu labeled Select the user account if not already selected.

Follow the prompts to reset the password. It's safest to choose a password that includes only the characters a-z, A-Z, and 0-9.

Select

 ▹ Restart

from the menu bar.

You should now be able to log in with the new password, but the Keychain will be reset (empty.) If you've forgotten the Keychain password (which is ordinarily the same as the login password), there's no way to recover it.

Don't you bother reading prior posts? Providing a slightly different procedure for the same thing is hardly adding anything new.