For security purposes, only the owner of an IMDb account may delete the account. We're unfortunately unable to delete accounts on behalf of our users.
In order to delete an IMDb account you no longer have access to the email, you would need to log in using the email and password you set at registration. If you can't remember the password, you can try to recover your account by visiting the recovery page and follow the instructions. Once recovered, you may then delete the IMDb account.