How did you install it on the first computer? Even though you can install it 5 times, it seems you can only use the CD 1 time unless you install it on another computer using the other operating system like Mac. And if you installed from the CD it seems you can not download it from online. You can't do both CD and download. See the info on this FAQ
https://ttlc.intuit.com/community/installing/help/i-bought-the-cd-but-my-computer-doesn-t-have-a-cd-...
Or try copying the CD to a usb flash drive. See SteamTrains post here
https://ttlc.intuit.com/community/taxes/discussion/why-can-t-i-install-turbotax-on-my-laptop-via-dow...
