It's that M$ people again! They do not provide OpenGL by hardware drivers for XP and newer operating systems. You need to download a driver drivectly from your card's manufacturer. In your case:
www.ATI.com
That's really a problem these days. Andy, you should check if OpenGL hardware support is available, if not give (one in the lifetime) a warning/hint what to do. This can cost you potencial customners otherwise.
HTH,
Gernot