Legacy audio drivers

Hello, I format my system ,after that my sound is not working.
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 2.70
512 mb of ram
give me the right solution.
thanks