After formatting my laptop there's sound

Hello,
I'm using Thinkpad R61 7734 n3u and i changed my OS to black xp sp2 and now there is no sound.when i go to device manager the audio device on high definition audio bus has a yellow question mark.i have gone through other people's questions most of the answers talk about soundmax but after checking mine does not have that option.i googled for audio drivers but they are not working.what could be the problem and what should i do.please help me I'm very frustrated.

Thanks in advance.