What happens in Win7 about create Ado Connect

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C++

Windows

ADO

My Program，use ado operation access DB, run very good in winxp.
but in win 7 have some depressed problem:

CAdoConnection::CAdoConnection()
{
//创建 Connection 对象---------------------------
m_pConnection.CreateInstance("ADODB.Connection");


it will suspend in m_pConnection.CreateInstance("ADODB.Connection"); 

specific Description:

  // Loads an interface for the provided CLSID.
  // Returns an HRESULT. Any previous interface is unconditionally released.
  //
  HRESULT CreateInstance(const CLSID& rclsid, IUnknown* pOuter = NULL, DWORD dwClsContext = CLSCTX_ALL) throw()
  {
  HRESULT hr;

  _Release();

  if (dwClsContext & (CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER)) {
  IUnknown* pIUnknown;
  hr = CoCreateInstance(rclsid, pOuter, dwClsContext, __uuidof(IUnknown), reinterpret_cast<void**>(&pIUnknown));


hang-up in hr = CoCreateInstance(rclsid, pOuter, dwClsContext, __uuidof(IUnknown), reinterpret_cast<void**>(&pIUnknown));

can not return any Error code;
please help me.