Sound suddenly stopped working

[rubyc]

The sound on my computer system suddenly stopped working.  I cannot hear anything when I plug headphones directly into my CPU, so it is an internal problem.  I checked devise manager and sound programming but nothing is wrong.  Everything looks to be working.  Any suggestions.

I have Gateway Pentium IV, Soundblaster card, Windows XP, DSL.

I download a lot of sound and video off of the internet.  Usually play through Windows Media Player, but I recently downloaded MusicMatchBox system to check it out.  It worked ok for the first few days.  I just have no idea why my sound would suddenly quit.  

Help is greatly appreciated.

[Raptor]

The CPU is an abbreviation for the Central Processing Unit. Soundcard or PC would be a better term.

I suggest you:

• Uninstall soundcard drivers
  
• Either update or reinstall previous soundcard drivers.
  
• Replace soundcard (If the two options described above fail)
  

You can also run a DX diagnostic.

(Windows XP)

Go to:

• Start
  
• Run
  
• Type DXdiag
  
• Go to the soundtab and the run the tests. See if any errors occur.