Important: to see your past purchases, register with the same email address you entered on the checkout page.
I'm getting an "Email address already taken" Error
Accounts are automatically created when a purchase is made, so it may be that an account has already been created for you. In this case, you can access the the account by logging in with your email address on the account login page. If you don't know the password, you can reset it using the "Lost Password?" link on the login page.