Hello, thank you for reaching out to Microsoft Q&A.
May I please confirm whether you performed a full factory reset? Specifically, did you choose the option to remove all of your personal files?
After resetting your PC to factory defaults, did you try setting up the device using your Microsoft account? Is it still asking for your administrator password on the Windows sign-in screen?
What is the exact error message you are seeing now, or which screen are you currently on?