I installed a PCI Firewire card in a Vista computer and it picked it up right away after restarting. It is a non descript card called a SOHO1394 and I didn't need to do anything to make it work. Check in System -> Hardware -> Device Manager to see if there is a IEEE 1394 Bus Host Controller, if it isn't listed, it may be a dud card or it may not be seated properly in the PCI slot.

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