Try going to the manufacturer's website and using the audio drives they supply under your particular model, they will have them under drivers/downloads area. (I'm assuming your computer is not a custom build, but without the info about your system from the link posted several times previously, I don't know anything about brand, model, etc.. and cant help pointing you in the right direction, so you'll have to find the site and enter in your model number to find the correct drivers, D/L them and install them.)
(also might be a hardware issue, we could try to rule that out next - esp. since the full clean install of windows you preformed should have make your system just as it was when it worked initially with windows 7)
Let me know,
Mike (I will be in and out today/tonight most likely)