If you forget your password, the system can e-mail you a link that you can use to reset it. In order to use this, you must remember your username and have supplied a valid e-mail address when you registered for an account.
To use the password reset, select the Login option on the top of your screen. In the window that pops up, you will see a link that says: Forgot your password? Click here to request a reset. Click on that link and follow the instructions on the page.