TV tuner card - TV cable causes sparks

I had wanted to install a TV tuner card in my dell dimension 4500. However, whenever I bring the TV cable (RF cable) close to the back of my computer, there would be sparks (between the cable end and the metal plate of the computer). This would happen even when my computer is off (and the TV tuner card is not installed). A friend of mine thinks there could be some grounding problem with my computer.

Would really appreciate any advise.

 

Cable for cable TV does carry a low level charge, and anytime you would touch that to another conductor there can be a spark. Perhaps unplug the cable from the wall before plugging it into your system if the spark worries you.