A common recurring theme I know but ...

recently acquired a Sony HDR-HC5E to video our latest family addition so that we could send stuff to relatives abroad. In order to connect to out computer, we bought a 4 pin to 6 pin firewire cable as the ilink cable supplied is 4 pin to 4 pin. While it worked the first time and we were able to download the video we had taken so far, I am now unable to get the computer to recognise the camcorder so can no longer download video. Any ideas?