Have you ever wondered how to get rid of the default Joomla 404 page and display a custom page that shows links or search results, so that your visitors can navigate to other pages with out feeling lost? Well, I have and I was googling a bit and found out the following:

You can replace the above page with a custom page that looks exactly the same as the rest of your website. Here is what you have to do:

• Create a new article page that you want to display for your users when they bump into 404 error. Please have a look on this website to get some inspiration how your 404 page should look like.
  http://www.smashingmagazine.com/2007/08/17/404-error-pages-reloaded/

• Now, in your “template” directory create a file called “error.php” and add the following code

<?php
defined( '_JEXEC' ) or die( 'Restricted index access' );
if (($this->error->code) == '404') {
header('Location: ' . $this->baseurl . 'my/404/article/page/url');
exit;
}

• “my/404/article/page/url” is the url of your 404 article page. Replace it with the new article page that you have just created.

• Now is testing time: Navigate to any page in your website and from the url of the page delete something and try to reach that location, your new error page should popup up.

• In your Joomla control panel or from top menu click on the Global configuration

• On the Global configuration page click on “site” tab. There, you will find “SEO Settings”

• Click yes on the radio buttons for “Search Engine Friendly URLs” and “Use Apache mod_rewrite”

• Now you have to go to your Joomla website root folder and find a file name called “htaccess.txt”

• Since windows explorer won’t let you rename “htaccess.txt” to “.htaccess”, you have to do this from dos prompt.

• Open dos prompt, change directory to your Joomla website root directory and execute this command

ren htaccess.txt .htaccess

• Now make the following addition into “httpd.conf”. the file is located here “<Drive>\xampp\apache\conf” . Find the following section

• Now find the following line in “httpd.conf”

“LoadModule rewrite_module modules/mod_rewrite.so”
Remove “#” from the beginning of the line if it exists

• Save your “httpd.conf” and your ready to use SEF URL on your Joomla website.