I teach a video class at SWHS and we are having a big problem that I have never encountered before. 4 Canon ZR830 cams and a GL2 have lost the function to transfer data through the ieee firewire port. All worked, then just started going down. The computer port works fine. I've tested the ports with external HD's and hubs and all work. The camera works great. WHen we connect the firewire cable to the camera and turn it on, nothing happens on the computer. The software says it is not detected.