Hello
Is the charter.net its own Windows login user? Does the gmail.com Windows user have admin rights?
If so,
Type sysdm.cpl in the search on the taskbar and hit enter, go to Advanced tab, click on the "Settings" button at the User Profile section. Then delete the old user profile.
Then, hold down Win+R keys, type in netplwiz and press enter, then find the charter.net user there and remove it from there.