Forgoten username/password

Does anyone know how i can access my digital editions if i dont know my authorisation username and password? I set the account up approx 7-8 years ago and the password recovery was on an old email account that i haven't used for around 6 years & can no longer access. My computer threw a wobbly and i have had to wipe it and re-install all the software but now i cannot authorise the computer and gain access to my ebooks. I presume it's because the software had not been de-authorised prior to the computer crashing and i cannot remember the password to re-authorise anyway.

Any help would be appreciated.

Thanks... Mark.