Simply goto http://www.lavasoft.com/support/supportcenter/ and sign in with your username and password. If you don't know the password, click the link " Have you forgotten your password or changed your e-mail address?" and enter your email address in the email field and click submit
Check you email. Then, start over. Once signed in, you will be presented with your licenses. Click the link E-Mail serial number. Then check you email. You will now have the message containing you registration information. I only hope it will actually allow you to register. I have been successful in the past, however, as of now I cannot reregister my software.
Hope this has helped!