Re: Mystery... Sound issue - not a plug missing....
Since you have a separate sound card, the first thing to check is to enter the Setup (F2 at power on) and verify the Integrated audio (on the motherboard) is disabled. If it's enabled it can cause sound conflicts and cause the SoundBlaster not to work.
The second thing, if you have a Video card with HDMI on it, some Video cards will want to set themselves as the default audio playback device and thus there will not be any sound. Check the Control Panel/Hardware and Sound and finally the Sound panel. In the playback, make sure your "Speakers" are set as the default playback device.
There have been problems with the SoundBlaster Xfi cards (not just with Dell but with all brands of PC's) and some have even removed the SoundBlaster sound card and started using the on-board (Integrated) audio because of the hassles. This is another option to consider or at least try.
Finally, if you have iTunes it has been know to cause various problems, in some systems (again it's iTunes and not the Dell as other brand PC's have also reported problems).
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