I recently had a headache with a Windows 7 installation to my work PC, I use Business Objects Enterprise (BOE) and more specifically Business View manager to manage the links that I use within Crystal Reports. However following installation of Windows 7 I couldn't get Business View manager to connect to any of my Microsoft SQL sources, however SQL server management studio had no problems.
After much head scratching and googling (with no help), I realised that I had installed SQL Server 2008 R2 and the SQL server I was trying to connect to was SQL server 2005. Just in case anyone else has the same problem hopefully this will result in an answer existing in google.
Grab you SQL Server 2005 disk and install the native clients, seems simple but myself and a colleague spent a few hours struggling with this!