关机程序关不了机

小弟测试一个xp的关机程序。但是老是效果不好按F9可以运行。但就是关不了机？？各位大侠看看哦！！
procedure Get_Shutdown_Privilege;//提权
var
    rl: Cardinal;
    hToken: Cardinal;
    tkp: TOKEN_PRIVILEGES;
begin
    OpenProcessToken(GetCurrentProcess, TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY, hToken);
    if LookupPrivilegeValue(nil, 'SeShutdownPrivilege', tkp.Privileges[0].Luid) then
    begin
      tkp.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
      tkp.PrivilegeCount := 1;
      AdjustTokenPrivileges(hToken, False, tkp, 0, nil, rl);
    end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
  ExitWindowsEx(EWX_FORCE+EWX_SHUTDOWN,0);
end;

end.