Ubuntu is kde styled after install AND removal
Remove from your $HOME directory any file that is of the form.gtkrc After removing such files, go back into your Appearance settings and change your theme to Ambiance or Radiance, apply, then move onto your preferred theme.
Please check the setting of Ubuntu in System Setting.
TO ensure you run the correct version, you should + Install unity GUi + Change setting + Reset computer again to change setting I guess you change on an account but check on other account