I tried all the suggestions made in the forum. Although none of them worked,. I found a new solution. I installed (successfully) TurboTax 2000 on an older Windows 10 laptop. Then I copied the entire contents of the installed Deluxe 2020 folder onto the new laptop. I double-clicked TurboTax.exe. was prompted for the registration code and got into the program. Problem solved. I have no idea why this worked, but it worked.
