Company: Elisa Research Inc.
Date:    05/23/97
By:      Henry

Symptom: 
    Sometimes when installing the driver in a WinNT, the 
    following error message appears:  

    "Setup is unable to obtain network adapter information 
    from the associated network adapter DLL files. Operation 
    cannot continue."

    The same problem is reported by Don, SMSC together with a
    solution.

Investigation:

    After two-day investigation. We found two things will affect 
    the result of the installation:
    1. the DLLs (LAN9000.DLL and LANNCDET.DLL) in the directory
       (default is \winnt\system32)
    2. the content of the NetCardDlls in the registry

    case 1:
    With a fresh installed NT, DLLs does not exist and 
    the content of NetCardDlls is clean. Duing installation, the
    INF checks NetCardDlls to see if LANNCDET.DLL is in it. Since
    it is not, it will 
    a. Copy the DLLs to the designated directory and
    b. Add LANNCDET.DLL to NetCardDlls.

    case 2:
    After DLLs (in directory) and LANNCDET.DLL (in NetCardDlls)
    are put in place, new installation will NOT copy the 
    DLLs (from floppy to hard drive) because INF detects the 
    existence of LANNCDET.DLL in NetCardDlls. This means a 
    new installation will NOT override the DLLs in the directory.

    So if user wants to do a new installation and also use the 
    new DLLs in the floppy, he will need to MANUALLY copy the
    DLLs over (as Dos's solution).

    One very confusing senario is the following:
    On an already installed NT, user deletes the DLLs manually 
    (without copying over the new ones). And since DLLs are no longer 
    existed, he would expect that the new installation will 
    automatically copy the DLLs for him. Wrong! The INF will
    detect the existence of the LANNCDET.DLL in the NetCardDlls in the
    registry, it will not copy the DLLs. And since there is no DLLs,
    the same error message shown before will appear. 

    From the above observation, it says:
    1. If user likes to use the new DLLs, he needs to manually copy
       them over.
    2. If DLLs are not in directory but LANNCDET.DLL is in NetCardDlls,
       all the following installation will fail.

    We did another experiment which is to copy the DLLs over regardless
    the contents of NetCardDlls (so that the new DLLs override the old
    ones in each installation). If failed with a "Copy violation error".
    The reason is that once INF reaches a certain step, ALL DLLs (not
    just the two we concern) are locked and any attempt to override
    them will trigger the violation error.

    Since NetCardDlls also plays a big role in the installation, we
    tried a few experiments but all failed. Deleting it from the 
    registery causes more unseen errors in the installation.
    Cleaning up its content did almost the same thing. Our suggestion
    is not to have user touches it.