I am afraid that I spoke too soon. When I started up today I was told to log on by AOL Mail, Bing, Facebook, ThinkBroadband and Radio Times. I then looked back at your suggestion that I might be running 'in private' mode and indeed you were correct. Apparently this the default for Windows 10 home. I then think that I disabled private mode. If I now drop a menu from the ... at the top right of the Edge window I see that, "New InPrivate window" is dimmed whereas, "New window" is not.
Now when I put the PC to sleep and then wake it I am not asked to log on but when I restart I am asked to log on. This is OK by me since I only restart about once a month. Of course, I do realise that things may change, but, I'll hope for the best and thanks for your help.
When you tell your PC to go to sleep its halts the computer there and saves all memory contents to ram then goes to sleep.
When coming out of sleep it reloads up that stored memory contents and it continues where it stopped.
I think you might have the browser set to block cookies or you are running in private mode, or the browser is set to clear everything when you close the browser.
If you are referring to Edge, every time MS updates Edge it resets the settings and you have to go through and set everything back up, why they do this I don't know, the favourites are still available once you enable them via the settings.
For the cookies, I only block third party cookies.
And where its doing it for other places other than this site, it rules out this site.
TBH I say its a cookie issue which can be affected by Privacy Browser Mode, Clearing content when closing browser, Cookies in the setting being set to block everything.