Windows 7 - creative sound card line in problem

i have this Creative Sound Blaster 5.1 Sound Card - High-quality surround audio from creative & i download that driver from here Creative Worldwide Support for win 7. its works great in win 7 but line in doesn't work in win 7. i have local made tvtuner card. to listen sound form tv tuner i need to enter the sound input to my sound card. that means one in the tv tuner out put & another in sound card input. the prob is the mute function does not work i cant mute line in, line in is always on. i use windvr to watch tv show. if i listen a song in pc i close windvr i cant mute it.but the same things work fine in xp. how do i mute line in ? plz help or suggest me a sound card that i mute linein in win 7 & also it should work in win xp. sorry for my bad english.

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