OpenGL version and Windows

Hello,

I am trying to use Vertex Array Buffer Objects in my application written in C++ with VS2005 on WindowsXP.
From what I read it these features should have been added in OpenGL 1.5, but it seems that they are missing in the OpenGL implementation that I have on my system.

Perhaps I have to install some OpenGL API ? if yes where can I find it ?
I really appreciate any advise.

Thank you

http://www.opengl.org/wiki/Getting_started#OpenGL_2.0.2B_and_extensions

Thank you