NVIDIA 9500 GT - Macbook pro and opengl

One of our customers is having a graphical problem with their Windows 7 basic 32 installation on a MacPro 2009 running a NVIDIA 9500 GT. Their listed driver is GeForce 331.65, which correlates to the results of a dxdiag report, but a printed vendor/version/extensions opengl report contains just the following:

Vendor: Microsoft Corporation
Renderer: GDI Generic
Version: 1.1.0
Extensions:
GL_WIN_swap_hint
GL_EXT_bgra

…which is as if the graphics card isn’t found by opengl at all. Has anyone got any clues or ideas about what could be the problem here?

Kind Regards,
Myk