From the PostgreSQL Administrators Guide (list of supported platforms):
Windows/Win32 x86 v7.0 2000-04-02 Client-side libraries or ODBC/JDBC. No server-side. Magnus Hagander
WinNT/Cygwin x86 v7.0 2000-03-30 Uses Cygwin library. Daniel Horak
So I guess PostgreSQL server will only run on NT. You can try VMWare or FreeMWare or something.