The login page provides a Forgot your password link if you have difficulty logging in. Click on the Forgot your password link on the Login page to reset your account.
You will need to submit the email address you used to register the account. If you have several email addresses that you could have used, you may need to submit each in turn to identify the correct email address.
You will be sent an email to the correct address with instructions and a link you can use to reset your password. It may take several minutes for this email to arrive. You should check your email spam folder if it does not appear.