Welcome to the community.
Have you used your email address for online billing with a TalkTalk account before?
Do you have the same account number? If you have a new account number you'd need to use a different email address for online billing as an email can only be registered to one account. If you've got the same account number you shoudn't need to complete registration. This guide should help with My Account registration.
One way around this issue is to just open a new free email account, such as Gmail or Hotmail and then use that to register your account.
As long as you set your email reader to pick up mesages from your main account and the free account you will not miss anything.
If you are slightly more adventurous, you could set Hotmail/Gmail to forward any TalkTalk mail to forward messages automatically to your main address.
In order for us to remove the address, we need to know the old account details and confirm data protection so If you fill out this form, where it asks for twitter name, enter: Forum Barry1955 , after you submit it you should receive a 12 digit reference code, if you post it in this thread, I can locate it, and once the details are confirmed we will respond via email.
Please dont post the account details on the open forum. Also can you update your forum profile with your current telephone number, this will make it easier for us to find your account in future.