Hi Gurdeep. I'm Greg, an installation specialist, 10 year Windows MVP, and Volunteer Moderator here to help you.
If you have the same Sound controller will the driver downloaded from Dell work, using your Service Tag number here: http://www.dell.com/support/home/us/en/19/Produ... ?
If not try the controller manufacturer's Downloads page for the make/model controller to make sure you've tried them all.
You can trace the hardware to be sure you have it correct:
http://www.sevenforums.com/tutorials/73420-hard...
As a last resort I sometimes install Driver Max for it's two free drivers a day, then uninstall it afterwards. It's the best at doing no harm.
Then you'll have tried everything and can decide to replace the sound controller.
I hope this helps. Feel free to ask back any questions and keep me posted. I will keep working with you until it's resolved.
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