CodeIgniter从url中删除index.php

Question

I know this question has been asked a number of times. However, I still wasn't able to get rid of index.php url. It is preventing me to access my controller directly.

I am current using CodeIgniter 2.2.2.
And the following is my .htaccess file:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
</IfModule>

application/config:

//  Find the below code

$config['uri_protocol'] = "AUTO"

//  Replace it as

$config['uri_protocol'] = "REQUEST_URI" 

Any Idea? Thanks in advance for your time.