Right click on the Start button.
Gufffaw! When I was scrounging around looking for my email contacts, one of the instructions was to click the START button. I never could find a START button. The only thing I found that resembled a START button was the POWER button to turn it off when I gave up for a while and took a break.
Another thing about it was that after W-10 downloaded and was set up and running, all my old icons were still on my desktop screen but most of them no longer worked. And I repeatedly got error messages telling me “This application is no longer valid, yak-yak-yak.” But the invisible START button was the final straw that caused me to say to blazes with this crap, and to restore W-7.