I have purchased Samsung S2 Portable 500GB hard drive. From one year it is working very well. When I was using it recently and plug it into my computer, it generated a sound that some device is plugged into pc but there was nothing. The disk works on another computer very well. I tried my external camera to use with this socket and it worked perfectly but hard drive is not working well. What should I do?? Any suggestions??. Any help will be appreciated. Thanks in advance.