In your case, you wouldn't have to disable the digital audio out, if you install the Realtek driver [from their website].
Check the following: Win 7 Control Panel; Hardware and Sound; Sound; Manage audio devices; Playback tab; verify that no digital output is the default. In the attached Picture, I have Speakers as the default and digital output disabled).
DRM and D* prevent us from using digital output unless it is DRM compliant.
I hope that helps. Best wishes!
If you look back in this thread, last fall Microsoft pushed an update that screwed up the playback, but Realtek's driver works fine [again].