Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

{ 
 Connect a handler to the Application.OnMessage event. 
 You have to do this in code: 
}

   private
     procedure AppOnMessage(var Msg: TMsg; var Handled: Boolean);
     { Private declarations }
   public
     { Public declarations }
   end;

    var
   Form1: TForm1;

 implementation

 {$R *.dfm}

 var
   FConnected: Boolean;

 procedure TForm1.AppOnMessage(var Msg: TMsg; var Handled: Boolean);
 begin
   if FConnected then
     case Msg.Message of
       WM_KEYFIRST..WM_KEYLAST,     // Keyboard events 
      WM_MOUSEFIRST..WM_MOUSELAST: // Mouse events 
        Handled := True
     end;
 end;

 procedure TForm1.FormCreate(Sender: TObject);
 begin
   Application.OnMessage := AppOnMessage;
 end;

 procedure TForm1.FormDestroy(Sender: TObject);
 begin
   Application.OnMessage := nil;
 end;

 procedure TForm1.Button1Click(Sender: TObject);
 begin
   FConnected := True;
 end;