Recently Microsoft released a security update to patch flaws.  Unfortunately that patch has been causing errors with systems that have RealTek's HD audio installed.  Particularly the control software.  Microsoft has released a patch to fix the flaw, however they will not be releasing it under the automatic updating system.  If you are experiencing this problem, please go to this page.  Download the file and install it.  A reboot will not be required, however you may wish to do so to make sure the error is gone.