Joomla! uses a special file called
htaccess.txt that is standard issue on all Apache web servers. This file allows commands to be issued to instruct the webserver to take actions based on certain conditions.
htaccess.txt file that is in every copy of Joomla!, has several specific instructions that offer some protection against specific types of hacks. Using this file helps avoid some common troubles that may visit your site.
Please note before you start that the following steps might already be done.
htaccess.txtin the root.
.htaccess(don't forget ...