// 안녕하세요  김영대(http://www.howto.pe.kr) 입니다  

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Registry;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  reg : TRegistry;
begin
  reg := TRegistry.Create ;
  try
    reg.RootKey := HKEY_CURRENT_USER;
    reg.OpenKey('Control PanelInternational', false);

    // 날짜 -> 간단히 표시
    reg.WriteString('sShortDate', 'yyyy-MM-dd');

    // 날짜 -> 자세히 표시
    reg.WriteString('sLongDate', 'yyyy''년'' M''월'' d''일'' dddd');

    // 시간 -> 시간 형식
    reg.WriteString('sTimeFormat', 'HH:mm:ss');
  finally
    reg.Free;
  end;

  SendMessage(HWND_BROADCAST,WM_SETTINGCHANGE,0,0);
end;

end.