function GetSysWow64Dir: String;

64-bit Windows only: returns fully qualified path of the SysWOW64 directory. This is the actual directory in which 32-bit system files reside. An empty string is returned if this function is called on 32-bit Windows, or if for some reason it fails to retrieve the path on 64-bit Windows (unlikely).

var
  S: String;
begin
  S := GetSysWow64Dir;
  // Must check the result -- an empty string is returned
  // if there is no SysWOW64 directory.
  if S <> '' then
    MsgBox('SysWOW64 directory: ' + S, mbInformation, MB_OK)
  else
    MsgBox('There is no SysWOW64 directory.', mbInformation, MB_OK);
end;