MySQL Configuration on Windows Box with Apache and PHP

I am new to PHP and as well as with MySQL, I have installed PHP 5.28, on win XP (with Apache 2.09) and it is installed properly (at least PHP and apache), as when I call phpinfo (), through a script, it shows the PHP Information. then I installed MySQL 5.1.30, and from MySQL command prompt I am able to creating tables, making queries etc. so i think it is also installed properly. Now I want to use MySQL with PHP, but seems that *MySqli* is not installed properly. as when I write a following script in a php page I get a error, that indicates that i have written the following script in a file say *testmysql.php*. *<?php

        $si = function_exists ( 'mysqli_connect' ) ;
        if ( $si )
        {
            echo ' MySQLi appears to be installed correctly ' ;
        }
        else
        {
            echo 'MySQLi <B> does not </B> appears to be installed. ' ;
        }

?> I understand that it is a configuration error somewhere, as I am new with PHP and MySQL, so i am feeling lost. I have uncommented following two lines in the php.ini *extension=php_mysql.dll extension=php_mysqli.dll * and as well these two lines are also uncommented in the httpd.conf (Apache config file ). *LoadModule php5_module d:/programs/php528/php5apache2.dll AddType application/x-httpd-php .php *and theseb two files are also copied in windows folder (means available with windows path).* php5ts.dll php5apache2.dll * any guess what i am doing wrong, i am sure that it is some configuration error. Prateek