怎样修改windows里的开始按钮的位图？

/修改var   Form1: TForm1;   StartButton: hWnd;   OldBitmap: THandle;   NewImage: TPicture; / 将代码放入FormCreate事件procedure TForm1.FormCreate(Sender: TObject); begin   NewImage := TPicture.create;   NewImage.LoadFromFile('C:/Windows/Circles.BMP');   StartButton := FindWindowEx                  (FindWindow(                     'Shell_TrayWnd', nil),                      0,'Button', nil);   OldBitmap := SendMessage(StartButton,                            BM_SetImage, 0,                            NewImage.Bitmap.Handle); end;

/还原procedure TForm1.FormDestroy(Sender: TObject); begin   SendMessage(StartButton,BM_SetImage,0,OldBitmap);   NewImage.Free; end;

for win98se/delphi 5.0通过。