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1st step : Try and use the speaker on both the audio port present on your desktop.(i.e the front I/O panel and the back I/O panel)
2nd step : Try and use any other good known headphones if available.
3rd step : Click on the link mentioned below and run MS FIX IT.http://support.microsoft.com/mats/AudioPlayback/
4th step : Update the latest audio drivers and BIOS from the support website (http://www.dell.com/support/drivers/us/en/19/DriversHome/NeedProductSelection)
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