Samsung Galaxy Tab 2 10.1 — User name and password lost

I was given a Samsung Galaxy Tab 2 10.1 after it had been in storage for a couple of years. The lady who gave it to me asked me to erase everything, so I did a 'reset back to factory default' with the command in Settings. What I did not know is this command erases everything except for the user name and password. Now when I try to establish a new account it won't let me do that because it remembers it already has a user and a password. Bottom line: If I can't defeat the remembered user name & password, this thing is no better than a paperweight. Can anyone help with this dilemma?