I might be within the 30 days to revert back to Windows 7, I really can’t remember; of course an initial attempt fails because to get to ‘settings’ to do the reversion, it is necessary to have a start menu… The irony would be delicious if it wasn’t so maddening.
“Those whom the gods wish to destroy, first they drive them mad…”
Update added 7th January... Oh joy! Oh rapture! I found the keyboard route to Settings, and after dire warnings from Microsoft about passwords being needed for Windows 7, my laptop is now back in the land of the Windows 7 living.
It may be, in fact it MUST be, that further updates to Windows 10 will fix my desktop computer in the fullness of time. And it is not just the start menu that is not working; all sorts of other, more subtle things do not work. For example, I plug in my iPad to transfer some pictures, and the computer fails to recognize it as a drive, even though iTunes comes up.
Meanwhile, to anyone with Windows 7 or 8.1 being inundated with messages telling them how good Windows 10 is and to upgrade now, my advice is wait! You have until around August 2016 to do it. Even Microsoft must be able to sort out the problems by then. And if you doubt that there are problems, just Google 'Windows 10 problems'.
From one who has spent 10s of hours trying to sort out this issue, you have been warned!