Don't hang your hat on always having online access to the forms ... you should always save at least a paper copy of the return itself only (not all the backup worksheets) and/or save a PDF in at least 2 places.
See this TurboTax support FAQ for accessing prior year online tax returns - https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/270...
If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created. TurboTax does not store online any returns completed using the desktop editions.
