How to recover my account

I have a Norton Antivirus product key for 3 PC for 2 years. I have installed successfuly on my wife's computer months ago. Now I am trying to install on my Surface Pro 3.

I can't login ... can't remenber my account email.

I create a new account but I have an error message.. something like "the product key is already linked to another account".

Please help me.