With the firewire connected to the PC and camcorder there is no digital connection. I'm using Windows XP and the video card, firewire and camcorder are all ten years old or so. Is it something simple like drivers?
What software are you using to capture? The camera won't just show up in Windows. Firewire is used to control playback of the device and the video stream is relayed over firewire, but you need a client program that is capable of controlling and capturing the footage sent over the line. It isn't the same as something like USB where you just copy files off.