What is the make & model of the card? Are you running 32 bit or 64 bit windows 7? Have you checked for the newest drivers on the sound card manufacturer's web site? Have you also checked to make sure your volume isn't muted.
i have 32 bit running. yes i all check. only error i found . here write on the packet of sound card PCl Sound card.(ssd-ess-4ch (ssd-gmi- 4ch (ssd-gmi- 6ch)