If you install an Windows NT 4.0 driver for a PCI device that has a Windows 2000 or Windows XP driver installed, in order to recover some lost functionality, the resources for the PCI device are reassigned, preventing Windows 2000 or Windows XP from communicating with the device.

NOTE: The Windows NT 4.0 driver does NOT determine if there is already a Plug and Play device driver servicing the device.

You should NOT install a non-Plug and Play driver for a PCI device that is currently being serviced by a Plug and Play device driver.