Thank you so much friends..well it was asked in one of the interview and i had answered the person that we can use co create instance or all helper methods invoked by cocreateinstance seprately ...
CoGetClassObject(rclsid, dwClsContext, NULL, IID_IClassFactory, &pCF);
hresult = pCF->CreateInstance(pUnkOuter, riid, ppvObj)
but it seems he was not satisfied..
Not i problem interviewer sometime asks weird question..:P
Thank you so much guys..