http://blogs.msdn.com/bobkjelgaard/archive/2008/03/04/why-doesn-t-my-kmdf-1-7-driver-install-on-windows-vista.aspxWell, the root to this current problem lies in the story behind my last post .  If I had waited a few hours, Windows Update would have deployed a required SP1 prerequisites package, and the driver I had successfully installed would have ceased working. en-USCommunityServer 2.1 SP1 (Build: 61025.2)