You installed the PNPISA driver to give NT some Plug and Play functionality. Then you said NO to install drivers for some device it detects. Perhaps you are in a hurry and are going to do it at the next reboot. Unfortunately upon detecting the device on later boots, NT will not give you the install prompt again. To force NT to do so, delete the key entry for the device under

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\pnpisa

Delete the device's key and NT will detect the device upon reboot and reset the key. NT will then give you an opportunity to install its device driver. Which key is it? You will have a key for each PNP device detected. Use the Description value to link devices to keys.