I did purchase 2017 one but I don't have CD-ROM or DVD drive. Where can I download SW on-line ?

Purchased 2017 tax return in 2018. But didn't get a chance to do during 2018. So I try to download 2017 tax return but I cannot find the place to download 2017.

(I do have product key and CD for 2017 tax return)

Where can I download like 2018 one.