Have you tried to do a Restore of your system, you can back up to 90 days?
If that didn't work, go here, scroll down to "Where Did My Sounds Go?":
*Top-10*Troubleshooting Windows XP, Tweaks and Fixes for Windows XP http://www.kellys-korner-xp.com/top10faqs.htm
Short list of possibilities, check cables. Then speaker
icon in tray, make sure nothing is muted. Do you get
sound when you plug in phones to sound card?
