Miscellaneous topics that do not fit into specific categories.
Open the Settings App
Go to Accounts - Other Users
Click 'Add Account'
Follow the prompts to create a new account with the correct credentials.
Close the settings app
Log out of that incorrect account
Log into the new account
Click the Start Button, type netplwiz and hit Enter
In the resulting dialog, select the old account and click 'Remove'
That's It, your new Admin Account will replace the old account