function TFrmMain.MyExitWindows(RebootParam: Longword): Boolean;
var
  TTokenHd: THandle;
  TTokenPvg: TTokenPrivileges;
  cbtpPrevious: DWORD;
  rTTokenPvg: TTokenPrivileges;
  pcbtpPreviousRequired: DWORD;
  tpResult: Boolean;
const
  SE_SHUTDOWN_NAME = 'SeShutdownPrivilege';
begin
  if Win32Platform = VER_PLATFORM_WIN32_NT then
  begin
    tpResult := OpenProcessToken(GetCurrentProcess(),
      TOKEN_ADJUST_PRIVILEGES or TOKEN_QUERY,
      TTokenHd);
    if tpResult then
    begin
      tpResult := LookupPrivilegeValue(nil,
                                       SE_SHUTDOWN_NAME,
                                       TTokenPvg.Privileges[0].Luid);
      TTokenPvg.PrivilegeCount := 1;
      TTokenPvg.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
      cbtpPrevious := SizeOf(rTTokenPvg);
      pcbtpPreviousRequired := 0;
      if tpResult then
        Windows.AdjustTokenPrivileges(TTokenHd,
                                      False,
                                      TTokenPvg,
                                      cbtpPrevious,
                                      rTTokenPvg,
                                      pcbtpPreviousRequired);
    end;
  end;
  Result := ExitWindowsEx(RebootParam, 0);
end;

procedure TFrmMain.Button2Click(Sender: TObject);
begin
  MyExitWindows(EWX_POWEROFF or EWX_FORCE);
end;