I have a rebel xt and recently a pc with windows 7 (64-bit). (I didnt have any problems with my XP PC, but alas, it had to be replaced.) I have switched from PC connection to PTP. Windows popped up an info box stating that drivers were being installed, then it said the driver could not be installed. My rebel shows in my computer as a canon eos digital rebel xt, yet, while connected to the PC, my camera flashes "busy", and continues to flash "busy" for as long as its connected. (the camera works great, otherwise.) When I switch back to PC connection, the camera is not recognized, but it does not flash "busy" when powered on. I have the latest firmware and zoombrowser ex installed. Any ideas?