A: When a client is configured to use SCCM 2007 for software updates, the policy of the machine is configured with the SCCM software update point as an intranet Microsoft update service location. To undo this, just use Group Policy to set that policy to Not Configured.

Navigate to Computer Configuration, Administrative Templates, Windows Components, Windows Update and set Specify intranet Microsoft update service location to Not Configured, as shown below. Windows Update will use the Microsoft servers again.