Firewire card problems with WinXP

I have a "VIA OHCI Compliant IEEE 1394 Host Controller" firewire card installed, and WinXP shows no conflicts in the Device Manager, however I can no longer get WinXP to detect the device, in the sense of it finding any firewire device plugged in. (my Sony DV camcorder) I used to be able to capture video fine, I'd simply plug the camcorder in, and XP would pop up its little box saying it found the camcorder. Now, it totally ignores the camcorder.

Originally, I thought perhaps the cable was broken, so I tested out both the cable on a G4 Mac, and the cable and camcorder worked fine. I then knew it was either the settings, or the card itself, so I removed the device, rebooted, and let WinXP re-install the device. Still, no go. The device is still there in Device Manager, with no conflicts, and I see a "1394 Connection 2" location under Network Connections. The card itself can't be broken if XP is detecting it, and the cable is fine since it worked in a Mac G4, so what's the problem? Everything worked, and then suddenly it stopped. I do think I installed XP SP1 between this "working to broken" period, and I tweaked my network settings, but I don't see how that would affect anything, especially after I removed, and let XP re-install the device. Any ideas whatsoever about what's wrong here?