If you remember the password you used with Adobe when you created your AdobeID, the email itself does not need to be in use to use the associated AdobeID.
You can use it (old) email and password both to register ADE and to login to the Adobe website for other services and id administration.
If you have forgotten the password you can't use the usual password recovery as that involves an email to the email address.
Try Live Chat and see if they can do anything to help. http://www.adobe.com/support/chat/ivrchat.html
If you do once gain access to your Adobe ID you can visit https://www.adobe.com/uk/account/account-information.html#myadobeid
and add an alternative (up to date) email address for recovery reasons.
I'm not sure if you can change the main email address: there is a slot on the page above to allow that but not sure exactly what it does and how it affects existing registered devices.