interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls,ShellApi,ShlObj;
procedure ExitWindowsDialog(Handle: THandle); stdcall; external 'shell32.dll' index 60; ....
procedure TForm1.Button1Click(Sender: TObject);
begin
ExitWindowsDialog(Handle);
end;