Thanks. But any time I try to use any of the MSI API calls in code I get
compiler erors.

eg I try
MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_INFO), newHandle);

...and I get

error C2664: 'MsiProcessMessage' : cannot convert parameter 2 from 'enum
tagINSTALLMESSAGE' to 'enum tagMSIMESSAGE'
        Conversion to enumeration type requires an explicit cast
(static_cast, C-style cast or function-style cast)

I've already installed the MSI SDK/ Platform SDK (Feb 2003), and
 added the \include\ and \lib\ directories to the Visual Studio path, but no
joy.

Thanks