Multiple Instances of Same Port in Add New Hardware Wizard

ID: Q182088

The information in this article applies to:
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 about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

When you are manually installing new hardware (such as a modem) using the Add New Hardware wizard, multiple instances of COM or LPT ports may appear as options in the port selection box.


CAUSE

This behavior can occur if there are duplicate entries for a COM or LPT port in the registry. Duplicate entries can occur if the computer does not contain a Plug and Play BIOS.


RESOLUTION

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" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

To resolve this issue, follow these steps:

  1. In Registry Editor, export the appropriate registry key (for backup purposes):


    HKEY_LOCAL_Machine\Enum\Bios\*PNP0400 (or *PNP0401) for duplicate LPT ports

    HKEY_LOCAL_Machine\Enum\Bios\*PNP0500 (or *PNP0501) for duplicate COM ports


  2. Delete the appropriate registry key:


    HKEY_LOCAL_Machine\Enum\Bios\*PNP0400 (or *PNP0401) for duplicate LPT ports

    HKEY_LOCAL_Machine\Enum\Bios\*PNP0500 (or *PNP0501) for duplicate COM ports


  3. Quit Registry Editor.


  4. Shut down and restart your computer.


  5. Click Start, point to Settings, click Control Panel, and then double- click Add New Hardware.


  6. Click Next, click Yes, and then click Next. Windows automatically locates the installed ports and re-creates the correct entries in the registry without duplicates.



MORE INFORMATION

Note that the procedure described in this article should be used only for removing duplicate ports in the Add New Hardware wizard. Do not use this procedure to attempt to correct other issues related to Device Manager. 


Keywords          : kbenv kbhw win95 win98 
Version           : WINDOWS:95
Platform          : WINDOWS 
Issue type        : kbprb

Last Reviewed: February 2, 1999