Sometimes you want your client to see a different page then the default 404 (page not found)
To do this you just need to add and entry to .htaccess file on your web folder:
ErrorDocument 404 /404err.php
404err.php is an example of the PHP page you want the Apache to serve instead of the apache default.
The problem is that with Internet Explorer this does not work- Internet Explorer gets the 404 header from the apache and shows the user it own 404 default error page.
To solve this issue start the PHP that serves as the error page (404err.php) with this line:
<?php header("HTTP/1.0 200 OK"); ?>
This overwrites the 404 (page not found) with a 200 (everything is great) response and make the Internet Explorer serve your page and not its own 404 default error page