Q:

"Class not registered" when using Microsoft. Web. Administration on Windows 7 after installing updates

A Windows 7 (64-bit) system runs the following code under Windows Azure Compute Emulator (SDK version 1.5)
Site site = new ServerManager();

which yields the following exception:

Retrieving the COM class factory for component with CLSID {B15183DD-75F9-42DF-8E57-C8B57692F134} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)). 

The class id mentioned in the message refers to a 32-bit .dll in Program Files (x86).  Since the Azure role code is 64-bit this won't fly. 
This behavior was not observed until some Windows updates were rolled in when installing Windows Phone SDK 7.1
How can this problem be best resolved? 

A:

The problem was traced to having IIS Express installed on the same machine - uninstalling it restored normal operation.