No longer have the program disks but want to open previous years TurboTax files. How?

you need the app installed and updated for each year you want to open. if you bought through Intuit/Turbotax contact support to see if they'll push a copy to you. if you bought from another website see if you can download load it. only 2019 through 2022 are available and can be updated.   your other choices, 1) find a friend with the apps installed and updated or 2) to get a printout there is a website, https://www.taxprinter.com/ where you can pay a fee to get a printout of each return. they are not affiliated with Turbotax/Intuit.  3) The IRS has transcripts going back 6 years. you can get online or by mail for free or file form 4506 and pay a fee to get copies of the returns

https://www.irs.gov/individuals/get-transcript  - free transcript - no state 

https://www.irs.gov/pub/irs-pdf/f4506.pdf  $43 per return - no state.