菜鸟求教一个关于SystemParametersInfo的问题，望高手不吝赐教

Question

    GetTempPath(MAX_PATH, @PathName);
    FileName:=string(PathName);
    BMPFileName:=FileName+'DgDDirskdhenflsa.BMP';
    FileName:= FileName+'DgDDirskdhenflsaw.jpg';
    if FileExists(FileName) then
              DeleteFile(FileName);
    Image1.Picture.SaveToFile(FileName);
    if   (FileName='')   Then
    begin
      Self.Close;
    end
    else
    begin
        try
           MyJPEG := TJPEGImage.Create;
           with MyJPEG do
           begin
             LoadFromFile(FileName);
             MyBMP := TBitmap.Create;
             with MyBMP do
             begin
               Width := MyJPEG.Width;
               Height := MyJPEG.Height;
               Canvas.Draw(0,0,MyJPEG);
               SaveToFile(BMPFileName);
             end;
           end;
          SystemParametersInfo(SPI_SETDESKWALLPAPER,1,pchar(BMPFileName),SPIF_UPDATEINIFILE)
        finally
            MyJPEG.Free;
            MyBMP.Free;
        end;
    end;程序如上，将Image控件装载的图片释放并生成BMP文件，然后使用SystemParametersInfo设为桌面壁纸
但是怪事出现了，运行了之后竟然神奇的发现Shell Hardware Detection服务被禁用…… USB接口无法用了求教是哪里出问题了，难道是SystemParametersInfo参数设置有误？

Answer 1

procedure SetWallPaper(AWallPaper: string);
var
  iad : IActiveDesktop;
  strFileName:WideString;
begin
  strFileName := AWallPaper;
  CoCreateInstance(CLSID_ActiveDesktop,
                   nil,
                   CLSCTX_INPROC_SERVER,
                   StringToGUID(SID_IActiveDesktop),
                   iad);
  iad.SetWallpaper(PWideChar(strFileName),0);
  iad.ApplyChanges(AD_APPLY_SAVE);
end;

Answer 2

可能不是这里的代码引起的
没发现SystemParametersInfo和这个Shell Hardware Detection（硬件自动播放事件通知）服务有啥关联

Answer 3

3楼大哥的代码运行到iad.SetWallpaper(PWideChar(strFileName),0);
就出现了地址错误……