You can in fact change your email on the link I provided above. You may want to check to see if you are blocking any pop ups as when you sign in it will pop up a window. Click the 'Logon Info' tab at the top and you will see the option to change email address.
Snow Dog, your issue sounds different. It sounds like you may need an account merge performed. Send an email to sales@stardock.com and be sure to include any email addresses you may have used with us.