Hi, ok thanks that has been some help. Here is your spec sheet:
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From that you should be downloading this software:
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Obviously you want the one at the top for Vista. If I were you though, I'd first go into the 'Device Manager' and see if you have a yellow question mark where the sound should be. If you have then apply the software. If however your sound device is listed then right-click on it and check its properties, you may need to enable something like 'Digital output' but without looking first its hard to say. Good luck