Hi there, when i first installed windows 7 a couple months back i also had this issue!
At the time i was using a Creative Soundblaster Audigy SE 7.1.
Anyway after browsing numerous forums i found the fix and since then i have had no issues what so ever.
What you do is this,
1. Right click speakericon in bottom right of the taskbar. Select "Playback Devices".
2. Left click "Speakers/Creative SB X-Fi/Default Device" then click Properties.
3. Click on the Sound Blaster tab, And tick the "Disable Sound Blaster Enhancements" box.
Sourced from: social.technet.microsoft.com/Forums/en/w7itproperf/thread/e28a135e-a167-46cb-bc4b-bf432b826d9a
Let me know how it goes Couldn't link due to first time post which is understandable