I FORGOT THE PASSWORD TO LOG IN IN TO 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.

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

Try resetting your password through single user mode:

1. Start your computer in single user mode: http://support.apple.com/kb/ht1492
2. The computer will show a black screen with white writing. Do not freak out. This is supposed to happen.
3. Type the following lines, and press enter after each line:

/sbin/fsck -fy

/sbin/mount -uw /

Important: Wait until you see the "root#:" prompt before typing a new line.

4. Choose the correct line below for your Operating System. Type the respective command and hit enter when you are done.

For Snow Leopard and Below:

launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist

For Lion and Above:

launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist

5. Now, type ls /Users

This will list all of the users of your computer.

6. Using the name of the account password you want to reset, type this:

dscl . -passwd /Users/USERNAME NEWPASSWORD

Make sure to type the username exactly as it appears in step 5. For example, if the username is "bob72", and you want to reset the password to be "123", you would type the above command as:

dscl . -passwd /Users/bob72 123

7. After executing the last command in Lion or newer operating systems, the computer may return an error about com.apple.DirectoryServicesLocal.plist. Ignore this message! If you properly typed the commands, the password reset worked anyway.

8. Once root# reappears, type reboot then hit enter. The computer will restart, and the account will have the new password.

9. Unfortunately, this process will cause problems with your keychain unless you suddenly remember your old password. When the keychain error appears, hit RESET KEYCHAIN. You will lose any saved passwords. While this is annoying, it is a necessary security feature.

I hope this helps!