Something mangled your image for the "factory reset". It should have walked you through connecting to a wireless (AKA WiFi) and creating a user account. Also, the Administrator account should not be appearing on the login screen.
The real key with Dell's is to go to
http://support.dell.com and type in the SERVICE TAG number which is on the same sticker as the serial number (on the bottom of the laptop) Once you are on the page, you can access the downloads, the service manual, and a whole lot more...
Did the PC come with Windows 10 and what is it's full model number (shows after you type in the service tag number)?