From the MS Windows 64 bit CMD window I get

c:\>echo %ProgramFiles(x86)%
C:\Program Files (x86)

c:\>echo %ProgramFiles%
C:\Program Files

c:\>echo %ProgramW6432%
C:\Program Files

From
GNU Emacs 23.1.97.1 (i386-mingw-nt6.1.7600) of 2010-05-04 on G41R2F1
I get
(getenv "ProgramFiles(x86)")
"C:\\Program Files (x86)"
(getenv "ProgramFiles")
"C:\\Program Files (x86)"
(getenv "ProgramW6432")
"C:\\Program Files"
In emacs, both the "ProgramFiles*" environment variables give the same
result.
I don't think that should be correct behavior.

Fortunately, Windows provides the ProgramW6432 environment variable.

What is the correct way in emacs to detect the two different locations in
which
Windows puts 32 bit and 64 bit programs?

Rich