Determine windows version: Win3.1/ Win95/ WinNT

Hi,

This is rather stale for todays standard's, but even then
Mine is a 16bit application, in which I have to determine, if the OS, it is being executed under, is
Windows 3.1/ 3.11 or Windows 95 or WindowsNT

I used GetVersion(), from Kernel.EXE, and extracted the Loword & Hiword, from it.
On Windows 95, it returns me the version (Hiword:Loword) as 3:95 but
on WindowsNT works4.0 and Win3.1 it returns me 3:10, in both cases.

Any clues?
I need this as I want to enable running multiple instances of my appl (in separate memory space) on WinNT but disable it on other OS's as there is no concept, of seprate memory space on them.

thanks in advance.
regards
Jeevan S