I only have a Windows 7 desktop computer. Can I use Turbo Tax 2020 Home & Business software? If not what do I do, I already bought it.

[NCperson]

the minimum requirement is now Windows 8. 

https://turbotax.intuit.com/personal-taxes/cd-download/tta-system-requirements

[VolvoGirl]

Find or borrow another computer you can install it on or ask for a refund and use the online version.

Contact Customer Service

 (You need to pick the CD/Download program in the product drop down box.) 
5am-5pm Pacific Time Monday -Friday
https://support.turbotax.intuit.com/contact/

What is the Turbo Tax phone number
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632