i forgot my password

First, make sure caps lock is not on.

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.

Otherwise*, boot into Recovery by holding down the key combination command-R at startup. Release the keys when you see a gray screen with a spinning dial.

When the OS X Utilities screen appears, select

Utilities ▹ Terminal

from the menu bar.

In the Terminal window, type this:

res

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

resetpassword

Press return. A Reset Password window opens.

Select your boot volume ("Macintosh HD," unless you gave it a different name) if not already selected.

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 your Keychain will be reset (empty.) If you've forgotten the Keychain password (which is ordinarily the same as your login password), there's no way to recover it.

*Note: If you've activated FileVault, this procedure doesn't apply. Follow instead the instructions on this page:

If you forget the password and FileVault is on

If you mean the keychain, that was reset (emptied) when you reset the password, as I wrote above. It was useless without the password. If you remember the password, restore the keychain from a backup.