NO Sound

Hai
right click "my computer"click "manage"click "device manager"click "sound,video and game controller
open(audio codes,legacy audio driver,legacy video capture device,media control devices,video codes. i can choose any of them it shows this device is working properly.i go to start menu, setting,control panel select sound and audio "it showes "no sound device" i don't understand whats going on my video device is working properly.but there is no sound
my computeris:-
system
microsoft windows xp
professional
version 2002
service pack 2
computer intel(R)
pentium(R)4
cpu 3.00ghz
1.00 gb of ram
give me the right solution.
thanks

Configuration: Windows XP
Internet Explorer 7.0