As stated - Close all TurboTax windows on your web browser (including this one). Copy and paste the account recovery website link onto a new web browser window and run the tool.
Use this TurboTax account recovery website to get a list of all the user ID's for an email address. Run the tool against any email addresses you may have used -
https://myturbotax.intuit.com/account-recovery
If none of the user ID's received will access your 2015 account, then use the option shown in blue on the account recovery website, "Try something else"
See Screenshot
