pWnd->SendMessage(WM_CLOSE) cannot close

[Students]

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

[Dan East]