What if my sign in was different for the tax year i need to retrieve...How do I pull it up?

Are you trying to retrieve a prior-year return that was prepared in a different account than the one you used for 2016?

Have you located the account with the prior return and can sign in OK, but it was prepared in Free Edition, so access is locked until you upgrade?    Or can you not find/sign into the other account at all?  

Did you prepare your 2016 return in Free Edition or a paid edition (PLUS or higher?)

Can you find your other account?   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     <a rel="nofollow" target="_blank" href="https://myturbotax.intuit.com/account-recovery/">https://myturbotax.intuit.com/account-recovery/</a>

Thanks

Thanks, ya'll; I finally got in!

That's good news.  Were you able to download the return you needed?

You can get a free transcript from the IRS:   
https://www.irs.gov/individuals/get-transcript