See the TurboTax Help article How do I view, download, or print a prior-year return? for guidance in accessing your return.
If you previously used a desktop CD or download edition of TurboTax installed on your computer, your tax data file and any PDFs created will be on the computer where your return was created. TurboTax doesn't have online storage for any returns you created using the desktop program.
You can also visit the IRS' Get Your Tax Record to access a transcript of a prior year federal tax return.