Why I am not able to transfer videos from my professional video camera to my computer?

Currently I am using a Nikon professional video camera. But the problem that I am facing right now is I am not able to transfer videos from my video camera to my computer. I had tried for transfer of video through data cable and Bluetooth both but I was unable to do so the only message that was displaying on both cases is an internal problem video cannot be transfer. I have got an original version of antivirus and scanned the flash memory of video camera but nothing happening. I had also reinstall the driver of video camera but unable to fix the problem. SO I want to ask from you people, what more I need to do?