// Let's check to make sure WP isn't already installed.
if ( is_blog_installed() ) {display_header(); die('<h1>'.__('Already Installed').'</h1><p>'.__('You appear to have already installed WordPress. To reinstall please clear your old database tables first.').'</p></body></html>');}
+$php_version = phpversion();
+$mysql_version = $wpdb->db_version();
+$php_compat = version_compare( $php_version, $required_php_version, '>=' );
+$mysql_compat = version_compare( $mysql_version, $required_mysql_version, '>=' ) || file_exists( WP_CONTENT_DIR . '/db.php' );
+
+if ( !$mysql_compat && !$php_compat )
+ $compat = sprintf( __('You cannot install because WordPress %1$s requires PHP version %2$s or higher and MySQL version %3$s or higher. You are running PHP version %4$s and MySQL version %5$s.'), $wp_version, $required_php_version, $required_mysql_version, $php_version, $mysql_version );
+elseif ( !$php_compat )
+ $compat = sprintf( __('You cannot install because WordPress %1$s requires PHP version %2$s or higher. You are running version %3$s.'), $wp_version, $required_php_version, $php_version );
+elseif ( !$mysql_compat )
+ $compat = sprintf( __('You cannot install because WordPress %1$s requires MySQL version %2$s or higher. You are running version %3$s.'), $wp_version, $required_mysql_version, $mysql_version );
+
+if ( !$mysql_compat || !$php_compat ) {
+ display_header();
+ die('<h1>' . __('Insufficient Requirements') . '</h1><p>' . $compat . '</p></body></html>');
+}
+
switch($step) {
case 0:
case 1: // in case people are directly linking to this