Turn it on.
Log in with your Microsoft account, while you do this, how about checking your security settings in your Microsoft account.
Turn on 2 factor authentication and or Microsoft Authenticator
Do all the Windows updates, this may take several reboots to do them all.
Remove the stuff you do not need, trialware, pre-installed antivirus from the apps or programs.
Install your own antivirus or let Windows Defender just run, check to make sure all the settings are activated
Install another web browser, I prefer Google Chrome turn off notifications in Google Chrome and make it your default
Install Adobe reader and make it the default for your PDF as Windows will want to use edge
Put your files back in the appropriate places, Documents in documents, Pictures in pictures etc
If you need your computer setup correctly please CONTACT ME