为什么SetWallpaper调用失败

void SetDesktopWallpaper()
{
HRESULT hr;
IActiveDesktop *pActiveDesktop;
CoInitialize(NULL); 
hr = CoCreateInstance(CLSID_ActiveDesktop, NULL, CLSCTX_INPROC_SERVER,IID_IActiveDesktop, (void**)&pActiveDesktop);
if (hr!=S_OK)
return;
WALLPAPEROPT   wpOptions;
wpOptions.dwSize   =   sizeof(WALLPAPEROPT);
wpOptions.dwStyle   =   WPSTYLE_STRETCH;
hr=pActiveDesktop->SetWallpaperOptions(&wpOptions,0);  COMPONENTSOPT   comps;
comps.dwSize   =   sizeof   comps;
comps.fEnableComponents   =   TRUE;
comps.fActiveDesktop   =   TRUE;

hr=pActiveDesktop-> SetDesktopItemOptions(&comps,0); 
//Insert code to call the IActiveDesktop methods
if(FAILED(pActiveDesktop->SetWallpaper(L"D;\\1.jpg",0)))
return; 
hr=pActiveDesktop->ApplyChanges(AD_APPLY_ALL); 

pActiveDesktop->Release();
CoUninitialize();}hr 返回一直是S_OK
执行完成后,桌面显示蓝色背景,且右键桌面属性->桌面图片就是设置的图片名  
为什么就是不显示?  哪位高手解答一下,谢谢