Uninstall the audio drivers completely using device manager, then delete the corresponding %windir%\inf\oemX.inf file, to make sure your system will never try to reinstall it. You will have to look inside the inf file itself to make sure it is the right one. Then download and install the latest official driver from the Intel page for your board. Don't try to get drivers from anywhere else. If you still have problems, make sure no other application is using excessive system resources to lag your system. Also, use VLC to play DVDs if you aren't already.