I got this from the OpenGL Game Developers FAQ to do what you suggest.

int pixelFormat = ChoosePixelFormat (hDC, &pfd);

PIXELFORMATDESCRIPTOR pfd_new;
DescribePixelFormat (hDC,...

I appreciated everyone taking time to give me some adivce here. let me tell you what I done since I posted last

Well have managed to get my app running full screen that wasn't a problem

but its...

Perhaps this should be a beginners question
but I'm not sure so I'll ask it here instead.

I've been using opengl for some time and now
I'd like to use the capabilities of my Voodoo2 card instead...