Are your drivers updated?

Hi! I'm having a similar problem on my computer. I've tried a lot of stuff, but still no success. I've got a lot of tips though, you can read all about them on this tread:
http://www.daniweb.com/techtalkforums/thread35649.html
Good luck!

Hi ... found this on another forum and it worked for me. Haven't tried it after reboot but it looks like a permanent fix.

Hope it helps

"I had this problem as well. It happened randomly in the middle of downloading music.
But thanks to some tech help from another site, the fix was pretty easy.

Go to Start --> Run, and type in services.msc.

A window will pop up with a list of services. Scroll down to Windows Audio. Right-click
and click on Properties.

Make sure that "Startup type" is set to automatic. Also, make sure, under "Service
status," start is selected. (Mine was somehow set on stopped. I clicked start and
-- voila! -- it worked.)

Hope this works for you, too."

A Windows update could also be responsible. Check the following topic:

April 3, 2007 Security Update For Windows Xp

sultan_emerr

i am not getting sound on my 2000 server its telling to install active mixer devices i try to reinstall the audio drivers but still no effect plz help me

i went to Start --> Run, and type in services.msc but i did not get windows audio option now what shall i do plz help me

I tried to fix a computer for 3 days with this problem ,i had to format and reload winxp .
i even deleted and disabled onboard sound and installed a pci sound card with the same results .remove recent installed program install by owner ,nothing tried all suggestions in this thread and other on this form like it nothing worked but a clean reinstall of windows for me .