4 NS chips have nothing to do with it. You first need to install the standard VGA addapter, and then you can install the 8500 drivers. Try installing the official drivers first if you are trying beta drivers.
Also, check and see if you have uninstalled your old drivers for your previous video card. That could cause problems as well. And making sure you have the latest Via drivers (4.38 are the current) tends to eliminate other posible issues.
Trollin' trollin' trollin', keep them doggies postin', my fingers are swollen, Rawhide!