Public Function ObjectExists(ByVal Class As String, Byref obj AS Object) As _
  Boolean
    Dim ob AS Object
 
    ObjectExists = false 
    Set obj = Nothing
 
    on Error Resume NoClassFound
 
    Set ob = CreateObject( class )
    If ObjPtr(ob) > 0 then
       ObjectExists = true
       Set obj = ob
    End if
 
    Exit Function
 
NoClassFound:
    Resume 
 
End Function

Dim o As Object
Dim wb As Das_Objekt_das_Du_Willst
 
If ObjectExists("Word.Application", o) Then
   Set wb = o
Else
   MsgBox "Fehler. Das geforderte Element: Word konnte nicht gefunden bzw." & _
     "geladen werden"
End If

Private Declare Function CLSIDFromProgID Lib "ole32.dll" ( _
    ByVal lpszProgID As Long, _
    pCLSID As GUID) As Long