Please be sure to take note of the following:
Select to use a server’s rewrite engine to catch URLs that meet specific conditions and rewrite them as directed. Available for IIS 7 and Apache.
Apache users only! – Rename htaccess.txt to .htaccess before activating.
IIS 7 users only! – Rename web.config.txt to web.config and install IIS URL Rewrite Module before activating.
To enable Use URL rewriting in Joomla 3
Step 1. Go to System => Global Configuration
Step 2. Select Yes to Use URL Rewriting under SEO Settings
Step 3 Click Save button.
Make sure mod_rewrite is enabled in the .htaccess
