Installing Multiple 3COM 3C509B PCMCIA Network Interface Cards

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe.

SYMPTOMS

On a computer that already has one 3COM 3C509B PCMCIA network interface card (NIC) installed, if you attempt to make the computer multihomed by installing another identical NIC, the following error message is displayed:

   Registry service subkey already exists. Unable to access services subkey
   and registry.

CAUSE

There are two entries in the registry that need to be deleted prior to adding the second 3COM 3C509B NIC.

RESOLUTION

To successfully install two 3COM 3C509B NICs on the same computer, follow these steps:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" online Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

1. Install the MS Loopback Adapter by using the Network tool in Control Panel.

2. Restart the computer.

3. Remove the first 3COM 3C509B driver.

4. Run Regedt32 and delete the 3COM key entries under the following two locations:

         HKLM\System\CurrentControlSet\Services\Elink3
         HKLM\Software\Microsoft\Windows NT\CurrentVersion\NetworkCards
   

   NOTE: There will be one number (1,2,3,…) for each adapter installed. Open each numbered key, and delete the key that contains the 3COM card information.

5. Restart the computer.

6. Install the first and second 3COM 3C509B cards by using the Network tool in Control Panel.

7. Delete the MS Loopback Adapter.

8. Restart the computer