No references to Microsoft.Office.Interop Assemblies

I have a new VS2010 C# project and want to add a reference to Microsoft.Office.Interop.Excel.  Unfortunately it is not appearing in the list of references on the .Net tab when I go to add a reference.  In fact there are NO references to anything beginning Microsoft.Office at all.

After much searching I found what I thought was the answer.  I need to download and install the Microsoft Office 2010 Primary Interop Assemblies - Redistributable package which I duly did.  

Instuctions for installing says to simply Double-click the O2010pia.msi.

However, after doing this the references are still not appearing.  

It's like pulling teeth... Why is it so difficult? That's the not question I want answering:)

Your help in this matter would be gratefully appreciated.