Hellow, Ive change my OS from Windows Vista to Windows Xp Pro and I got no sound now. I have tried to fix it for hours by googling and trying to find a solution. Ive downloaded plenty of softwares I found on guides from people to fix this PROBLEM but Its still not fixed.

I get the ERROR "no active mixerunits are available. You can install this by..." Or something similar to that. Ive tried what the error says but with no success.

The only sound i hear is "BEEP" And its really annoying . Please help me

And i dont know what ...sound card i have. I only know its Audio-Codec

Thanks in advance.You need to install both the chipset driver and the driver for you sound card. You can download and install Belarc Advisor (http://www.belarc.com/free_download.html) or Everest (http://www.lavalys.com/) to get a list of the hardware on your system.Thanks for the fast reply .
I did use both of them but I COULDNT figure out what kind of audio card I have.

Im missing a "PCI Device" and thought that could be whats causing this, I tried fixing it but its not working for some reason. Any Idea where I can download PCI Device?I don't know what you mean when you say you are missing a PCI device. Is this a genetic problem or do you see a MESSAGE SOMEWHERE on your system?

And again, you need to install the chipset driver first - did you do that?A missing PCI device means you DON'T have your MBoard chipset drivers installed...or there the wrong ones.
And these should go first so address this 1st.