I am using Dell Inspiron 6400 laptop running Windows XP Media Center Edition with SP3. Last 2-3 days ago, I started having issues with the sound and it only works through headphones, whether from a website or a CD/DVD or a file on the pc. I tried restarting but that didnt help either. Dell Diagnostics test is working fine and I can hear sound from the speakers while it was running. The Device Manager shows no issues. Is there any other solution? Thanks.