I am no longer getting the same error, but nothing works. Programs and features in the Control panel only shows .NET 4.5 installed. I tried to install .NET 2.0 but got an error that said it was already installed, and the repair tool only offered to fix 4.5. Hubby said he installed 2.0, but like I said it's not showing up in Programs and Features.
I tried downloading a book again, but it wasn't added to the directory they usually go to. I can see that it is still authorized to my account.
Here's a screen print with the available options showing in the file menu. I tried creating a new bookshelf and apparently that worked, but does me no good. Hopefully someone will have a suggestion before one of my library books is available. I am next in line for one of them.