I would be most grateful if someone could please help with the following.  

I have an installation routine which needs to check what platform it is
operating on (this is needed for knowing whether to install a 16 or 32 bit
version program).  Trouble is because the installation program is written
in 16 bit, NT responds to the GETVERSION API saying it is also a 16 Windows
version.  Clearly NT has decided because I have been asked by a 16 bit
program I had better tell it I am capable of running 16 bit programs.

What API should I call to get the true state of a Windows operating
platform?

Thanks, in advance.

Mark Thompson