Did you buy the CD or the download?
If you need to download your program…..
Access your downloads here
https://shop.turbotax.intuit.com/commerce/account/secure/login.jsp?pagecontext=download
If you have old .tax files you can try converting them to pdf files at Www.Taxprinter.Com
It might be expensive. They are not connected with Turbo Tax. Use it at your own risk.
You must have the 2015 program to open the 2015 .taxfile so you can save it as a PDF ... Always save the return as a PDF with and without the worksheets right after it is accepted by the state and IRS so you don't run into this issue later.
Contact TurboTax support and speak directly with a TurboTax support agent concerning this situation.
See this TurboTax support FAQ for a contact link and hours of operation -https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number