This update has been installed on my two machines even though none of them have any of the listed CPUs. Any ideas why this update seems to install on machines not affected?

Ok, sorry about that. It seems like others have the same problem but no solution:

Why does Windows 10 only allow the left mouse button for user - Microsoft Community

If you by lock screen means the screen that shows time and date and you click on it to get to the login screen, then here are instructions how to disable it. I have done it on my computer.

Enable...

I do not have an answer for your question, but have you consider disabling the lock screen as a workaround?

Thank you Brink, I have been helped several times by this forum but have not register an account until now. Thought it was about time to join and be able to return the favours.

Thank you for this information, I often found myself looking for "Select all" without luck in the context menu.

As I have a Swedish version of Windows 10 I edited the REG-file to say "Markera...