drupal install: pdo, gd not recognized but installed

Hi, I installed WAMP on Windows 7 yesterday, but I can't get Drupal to install on it. It complains that there is no pdo or gd module available, though the php extensions are checked in the .ini file (php_pdo_mysql. php_gd2). I ran a test to check that the extensions were installed:
(if (!defined('PDO::ATTR_DRIVER_NAME')) {
echo 'PDO unavailable';
}
else {
echo "ok!";
}

and the test ran ok. The error messages the drupal install gives me are:

Error
PHP extensions Disabled
Drupal requires you to enable the PHP extensions in the following list (see the system requirements page for more information):
gd
Error
Database support Disabled
Your web server does not appear to support any common PDO database extensions. Check with your hosting provider to see if they support PDO (PHP Data Objects) and offer any databases that Drupal supports.

Any ideas? Really appreciate it...