Did you read the readme where it says
If you already have an XF86Config file working with a different driver
(such as the 'nv' or 'vesa' driver), then all you need to do is find
the relevant Device section and replace the line:
(or Driver "vesa")
In the Module section, make sure you have:
You should also remove the following lines:
if they exist. There are also numerous options that can be added to
the XF86Config file to fine-tune the NVIDIA XFree86 driver. Please see
Appendix D for a complete list of these options.
Once you have configured your XF86Config file, you are ready to restart
X and begin using the accelerated OpenGL libraries. After you restart X,
you should be able to run any OpenGL application and it will automatically
use the new NVIDIA libraries. If you encounter any problems, please
see the FREQUENTLY ASKED QUESTIONS section below.
Please give us more information about what you did so that we may help you.
Thank you for your time,