How do you remove the "user login" block?
You may disable block on admin/structure/block page, but users can create new accounts from /user page. It's best practice disable creating new accounts by visitors.


For drupal 7 go to configuration -> people -> account settings -> registration and cancellation and set "Who can register accounts?" -> "Administrators only".
For drupal 6 go to administer --> user management --> user settings and set "Public registrations" --> "Only site administrators can create new user accounts."