Locating Primary Interop Assemblies
On the surface, primary interop assemblies look like any other assemblies. Although publishers can adopt a naming convention to clarify that the assembly is the primary interop assembly, they are not required do so. Thus, it is important for you to ask the publisher for confirmation if you are uncertain of the status of an assembly.
Primary interop assemblies are distributed either as files that you download or as setup programs that you can activate. The latter often installs and registers one or more primary interop assemblies for you. Some primary interop assemblies are distributed with Microsoft Visual Studio 2005 and are referenced automatically at design time. These assemblies are already registered under the same registry key as the original type library.
For more information about the availability of individual primary interop assemblies, contact the COM component vendor directly to request download locations.