I reset my laptop with Windows 10, but it does not start again with a setup, but I come to the normal log-in screen. However I do not know what username and password are. Can I reset Windows again, or log in elsewhere without using elaborate tricks?
Resetting Window 10 often does not work reliably.
As an alternative to reinstalling you can also do an "inplace upgrade repair" while retaining all the data, but you must also be able to log in to Windows:
https://www.deskmodder.de/wiki/index.php?title=Inplace_Upgrade_Windows_10_schnell_reparieren
To log in again, there's a trick, which is described here (section 3. Resetting the Windows password of a local account)
