106: Working with Users in Joomla 3
How to Disable User Registration in Joomla 3.1
Not all websites need to allow users to register for accounts. You can disable user registration in Joomla 3.0, and we'll show you how in this tutorial.
How to hide the login module in Joomla 3.1
If you no longer want to show the login form on your Joomla 3.0 website, you can hide it by disabling the login form module.