I reset my old laptop and when I started it I had to log in. But there was only one account named "Other user". No matter what I entered there was always username or password wrong. Windows 10 is on the laptop.
Try the following:
press the keys "Ctrl", "Alt" and "Del" simultaneously
A menu should open
click on "unsubscribe"
the computer then goes into start position
After about 3 minutes you then enter your known login data.
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If then "other user" is there again, then you may need to re-register. (new username, new password)
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I recommend to inquire at a retailer and to activate everything correctly on site.