finally thanks to jackvern from avsforum.com.also had to disable audio in the bios.
1. Go to "Control Panel" , click icon "Add or Remove programs", find any “Microsoft UAA Bus Driver for High Definition Audio" and uninstall it.

2. Open control panel again , click the icon "System", go to "HARDWARE" tab, then open the "device manager" , then go to "Sound and video game controllers" if you see any “Microsoft UAA Bus Driver for High Definition Audio" left click disable it and uninstall it.

3. Go to "device manager again, check at the "System Devices" if there's any “Microsoft UAA Bus Driver for High Definition Audio" left click disable it and uninstall it. Here ends the Bus driver cleaning steps.

4.Now you can successfully install realtek driver from your motherboard Driver CD and enjoy the sound.
Now to those wheel bearings on the disco