First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/OR you used the Desktop CD/Download program. Then the return is only on your computer and not stored online.
If you can't find your return, request a free transcript of your federal return from the IRS.
http://www.irs.gov/Individuals/Get-Transcript Or order an exact copy of your tax return (including all attachments) from the IRS. There is a $50 fee per tax return. See
http://www.irs.gov/taxtopics/tc156.html
