I’m using Windows Vista and Windows XP. Enabling cURL (Client URL Library) of PHP is really easy and is a matter of uncommenting something only.
Open your php.ini. I use XAMPP for development, XAMPP’s php.ini can be found in C:xamppapachebinphp.ini. You can probably find your copy lurking around there if you use XAMPP.
Do a search of ‘curl’ in the php.ini, there’s probably only one.