Came in to a login screen. When I logged in, it told me that there had been an update. Had a splash screen that you could only hit “okay” on.
Tried to start my POS, it said “You need to re-activate this product. The serial number used to register this product or your computer settings have changed.”
Dealing with a hundred or so PCs at work, we’ve had a couple of demands for reactivation. Entering the product number that was on the chassis was accepted.
It really sounds to me like you’ve been hacked. But I’m not an expert in these things.
It has happened to me that a Windows update cleared my cookies, and I had to type the passwords into every low-risk website that I usually let the browser handle. But I’ve never had it change registry information, which is what you are describing.
Something inthis latest update damages the Windows user profile a bit. A little Googling will find other people with the issue. Obviously it only affects a few percent of the Windows population, so its an interaction with some subtlety of those machines’ particular config or history.
In my case it manifests as Outlook still knows all the several accounts I have it configured to connect to. But it doesn’t know any of the passwords. When I put the passwords in, Outlook is happy. But a few minutes later it’s forgotten some, not all, of them again.
Separately I keep getting Windows notifications to “repair” the various accounts in either the old fashioned credential manager control panel or the new-style “email accounts” settings page.
In each case the accounts are known, the passwords aren’t. Fill them in and everything works. Until I reboot or restart Outlook or Onedrive or Onenote or …
Clearly something is mucked up in the user profile that is causing the “save” function to fail silently.
I’ve historically hated Windows so much that I have vowed that if I am ever allowed access to time travel technology, I would skip the “killing Hitler” trope and go straight to the “destroy Windows before it was created” route.
Last weekend M$ finally said it was ready* to "up"date my desktop (a homemade with an ASUS motherboard). Several passes and 5+ hours later Windows said it couldn’t find my boot drive; fortunately after several tries it gave up and (mostly) rolled things back. Not as disastrous an experience as the OP’s — nowadays I mostly use that computer when I need to do some programming or heavy-duty number work — but it will be a while before I try it again.
(I did set a restore point before proceeding, but it looks like the "up"date wiped out all the existing restore points. So next time — if there is a next time — a clone will be in order.)
*When 2004 was first released the message I got was that I would get the "up"date when my computer was ready, not when the software was ready. I found that somewhat whimsical.
