I have tried everything, including what you have suggested, but thank you for the suggestions anyway. When trying to recover to an earlier time, the option is greyed out thus eliminating that possibility. Using the recovery disk also greys out the option to keep files and the option to keep files and programs. The only option left is to destroy everything on the computer. This will prevent me from using the programs that came on the computer when I bought it. The computer is, or was it seems, an expensive 27" Samsung touch screen desktop.
I would strongly advise anybody who is considering trying the Windows Insider not to do so. I did voluntarily try out the Insider on my Microsoft Surface Pro 3 but it totally messed up the computer and I had to install Windows 10 again from scratch and lose all my programs and data. Fortunately there was not much on there so it was not a huge problem. I don't see that Insider is much different that a virus since it does the same amount of damage in the long run, i.e. it requires a total re-installation to get rid of it.
Unfortunately, I have not made a disk image for some months, but I suppose using the old one is better than nothing. However, that will require some considerable time in re-installing my recent programs.