Ladies and Gents, I also came across this annoying issue and here's how I fixed it:
The problem is caused by the OS not loading the Realtek HD Audio driver(s) before the service is started.
To fix it, I simple removed the Realtek HD audio device (un-install from devmgmt) and then reinstalled (preferably with Realtek's latest driver package: Available HERE
Simply reboot after the driver is reinstalled and that should do the trick. Don't get a fright if the red X is still there DIRECTLY after explorer.exe loads as it will disapear once the OS is fully loaded.