Tv Card Doesn't Give Out Playback Sound

Please, does anyone know what I can do to solve this problem with my Mercury TV card. The problem is that anytime I uses it to record, the playback just won't give out sound, I've tried adjusting the volume under audio properties, but doesn't seem to solve the problem.
I'll be very grateful if anyone could please give me a possible solution to the problem. Thanks in advance for your responses.