Canon Rebel XTi not recognized when plugged into usb

Have Canon Rebel XTi and HP Pavillion dv2000 with Windows Vista Home Premium. Installed software on EOS digital solutions disk that came with camera. When I try to connect via USB with camera on, I keep getting an unrecognized USB device error. I have tried several different USB cords - not the problem. I have connected other usb devices to port and they work so port not problem. How do i get computer to recognize the camera