delphi写的服务程序，服务起动后关不了机

delphi写的服务程序，服务启动后关不了机
各位大虾，小弟最近在用delphi写一个服务程序。服务程序的功能是启动一个带有界面的托盘程序。可在这个服务运行的时候，点关机，机器没反应。必须要停止该服务之后才能正常关机。小弟新手，特此发帖请各位大虾帮忙看一下，万分感激。程序分两个部分，代码如下:
1.服务程序部分
unit Unit_Main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, SvcMgr, Dialogs,Unit_FrmMain;

type
  TDelphiService = class(TService)
  procedure ServiceContinue(Sender: TService; var Continued: Boolean);
  procedure ServiceExecute(Sender: TService);
  procedure ServicePause(Sender: TService; var Paused: Boolean);
  procedure ServiceShutdown(Sender: TService);
  procedure ServiceStart(Sender: TService; var Started: Boolean);
  procedure ServiceStop(Sender: TService; var Stopped: Boolean);

  private
  { Private declarations }
  public
  function GetServiceController: TServiceController; override;
  { Public declarations }
  end;

var
  DelphiService: TDelphiService;
  FrmMain: TFrmMain;

implementation

{$R *.DFM}

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  DelphiService.Controller(CtrlCode);
end;

function TDelphiService.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;

procedure TDelphiService.ServiceContinue(Sender: TService;
  var Continued: Boolean);
begin
while not Terminated do
begin
Sleep(10);
ServiceThread.ProcessRequests(False);
end;
end;

procedure TDelphiService.ServiceExecute(Sender: TService);
begin
while not Terminated do
begin
Sleep(10);
ServiceThread.ProcessRequests(False);
end;
end;

procedure TDelphiService.ServicePause(Sender: TService;
  var Paused: Boolean);
begin
Paused := True;
end;

procedure TDelphiService.ServiceShutdown(Sender: TService);
begin
gbCanClose := true;
FrmMain.Free;
Status := csStopped;
ReportStatus();
end;

procedure TDelphiService.ServiceStart(Sender: TService;
  var Started: Boolean);
begin
Started := True;
Svcmgr.Application.CreateForm(TFrmMain, FrmMain);
gbCanClose := False;
FrmMain.Hide;
end;

procedure TDelphiService.ServiceStop(Sender: TService;
  var Stopped: Boolean);
begin
Stopped := True;
gbCanClose := True;
FrmMain.Free;
end;

end.


2托盘程序
unit Unit_FrmMain;

interface

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

const
WM_TrayIcon = WM_USER + 1234;
type
  TFrmMain = class(TForm)

  Timer1: TTimer;
  Button1: TButton;
  procedure FormCreate(Sender: TObject);
  procedure Button1Click(Sender: TObject);
  procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
  procedure FormDestroy(Sender: TObject);
  procedure Timer1Timer(Sender: TObject);
  private
  { Private declarations }
  IconData: TNotifyIconData;
  procedure AddIconToTray;
  procedure DelIconFromTray;
  procedure TrayIconMessage(var Msg: TMessage); message WM_TrayIcon;
  procedure SysButtonMsg(var Msg: TMessage); message WM_SYSCOMMAND;
   



  public
  { Public declarations }
  end;

var
  FrmMain: TFrmMain;
  gbCanClose: Boolean;

implementation

{$R *.dfm}

procedure TFrmMain.FormCreate(Sender: TObject);
begin
FormStyle := fsStayOnTop;
SetWindowLong(Application.Handle, GWL_EXSTYLE, WS_EX_TOOLWINDOW);
gbCanClose := False;