Thanks for the help. It has three antennas, all screwed on tight. I'll try to remove the D-link network manager software and see what happens. The new card will require some drivers... will Windows be able to supply those for me if I remove the manufacturer software?
There was one other thing that may have complicated the process. There was a Hauppage TV card in the PCI slot prior to the new network card. The TV card was never used during the many years that I had the computer, and I'm not sure if there is even any software for it installed. A quick look through the installed programs doesn't show anything labelled 'Hauppage'.
Anyways, I've got to go watch the Canucks beat the Sharks (on TV). But I will try the software removal after the game...