To unlock your account and reset your password, use the Forgot your Password? link available on the login page.

To use the Forgot Your Password? link:

1) Enter your username (in "username.enterprise" format, or the Email address assigned to your account)
2) Click the Next button
3) Confirm your identity by answering the security question and enter the last four digits of your phone number. 
4) Click the Next button
5) You will be assigned a randomly generated password to use the next time you login.  Copy this password (highlight and press Ctrl+C simultaneously) and paste it (Ctrl+V) into the Password field upon your next login.  Once you login successfully, you will be prompted to change your password to something more unique and personal.