pWnd->SendMessage(WM_CLOSE) cannot close

I use this code.
CWnd* pWnd = CWnd::FindWindow(NULL,_T("Windows Media")
if(pWnd)
{pWnd->SendMessage(WM_CLOSE);
This work when the WMP stop playing the file.
Cannot when WMP is still Playing the file.
Thanks
CWnd* pWnd = CWnd::FindWindow(NULL,_T("Windows Media")
if(pWnd)
{pWnd->SendMessage(WM_CLOSE);
This work when the WMP stop playing the file.
Cannot when WMP is still Playing the file.
Thanks