No audio,no sound device found

hi,

i have newly installed windows xp in my pc but there is no sound coming i have tried all these;
right click my computer-properties-device manager-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 even tried to go to Start-Control Panel-Adminstrative Tools->Services then found services Windows Audio opened-changing it to Automatic from.
i don't understand whats going on ,my video device is working properly but there is no sound
help me