Help attaching to a PCI device

My computer has a Netgear 83815 card that I need to communicate with. I
copied the first sample program listed in the pci_attach_device()
documentation, at
… I changed the lines:

inf.DeviceId = PCI_DEVICE_ID_ADAPTEC_2940F;

inf.VendorId = 0x100b;
inf.DeviceId = 0x0020;

to reflect the Netgear card’s values. When I run this program, the
pci_attach_device() call fails.

When I run “io-net -d ns83815” at the command line, I get the response:
unable to init dll devn-ns83815: No such device

One of my coworkers claims the problem is that the operating system is
“grabbing” the device for itself, so other programs can’t attach to it.
I’m supposed to find a way to keep the OS from claiming this device on
startup. Does anyone know how to do this?

Thanks in advance.