How can I get TurboTax 2008 software?

I purchased 2008 Turbo Tax back in, well, 2008. I have the .tax files, but not the software. To my astonishment, my state is now requesting information for which I need my return. I cannot get one from the IRS, as they do not go back that far. Doesn't seem to be a way to get the 2008 software, nor is there a way to open the files. Any suggestions as to how to get the software?