How to access last years return if using a new computer that does not have the turbo tax loaded?

If you used TurboTax online last year, you just need to sign in with the same user account.

If you used the desktop product, you should have a *.tax2016 file on your computer or a PDF file from last year that you can transfer into either online or desktop TurboTax.

Here's some info to help you:

https://ttlc.intuit.com/replies/3302290