uses ShlObj,ActiveX;

procedure TForm1.Button1Click(Sender: TObject);
var
  BI: TBrowseInfo;
  Buf: PChar;
  Dir,
  Root: PItemIDList;
  Alloc: IMalloc;
begin
  SHGetMalloc(Alloc);
  Buf := Alloc.Alloc(Max_Path);

  // CSIDL_BITBUCKET  RecycleBin
  // CSIDL_CONTROLS   ControlPanel
  // CSIDL_DESKTOP    Desktop
  // CSIDL_DRIVES     My Computer
  // CSIDL_FONTS      Fonts
  // CSIDL_NETHOOD    Network Neighborhood
  // CSIDL_NETWORK    The virtual version of the above
  // CSIDL_PERSONAL   'Personal'
  // CSIDL_PRINTERS   printers
  // CSIDL_PROGRAMS   Programs in the Start Menu
  // CSIDL_RECENT     Recent Documents
  // CSIDL_SENDTO     Folder SendTo
  // CSIDL_STARTMENU  The whole Start menu
  // CSIDL_STARTUP    The Autostart Group
  // CSIDL_TEMPLATES  Document templates

  // use of the constants above
  SHGetSpecialFolderLocation(Handle, CSIDL_PROGRAMS, Root);

  with BI do
  begin
    hwndOwner := Form1.Handle;
    // NIL means show all
    pidlRoot := Root;
    pszDisplayName := Buf;
    lpszTitle := 'Choose Folder';
    ulFlags := 0;
    lpfn := nil;
  end;

  try
    Dir := SHBrowseForFolder(BI);
    if Dir<>nil then
    begin
      SHGetPathFromIDList(Dir, Buf);
      ShowMessage(Buf);
      Alloc.Free(Dir);
    end;
  finally
    Alloc.Free(Root);
    Alloc.Free(Buf);
  end;
end;