thast woudl suggest the php / Mysql installation is damaged or not installed
try running the php function phpinfo() in a script
PHP Code:
<?php
echo 'PHP is working.<br>';
echo phpinfo();
?>
examine the results it should tell you what database connections are installed.
my suspiscion is that you will either need to repair to reinstall PHP and possibly the webserver. if you have to do that either get someone who is experienced in doing it or consider downloading the XAMPP relevant to your OS
as this is a PHP problem not a MySQL problem you may be better off asking PHP related questions there