well when you start your windows do you hear any sound ???
check out if it was set on mute !!!!
right mouse click on my computer >properties>hardware>device manager>then search for the sound card or any audio device and check if there's an "!" mark or "?" mark on a device if you found it then right mouse click on it then click on properties>details>update>then update your device using the sound card CD or disk that came with it
then specify the drivers location thenclick next wait as it finish installing then restart your pc
good luck if you found any prob reply to me so I could help you more