You receive a "Windows was unable to install the modem" error message when you try to install a modem on your Windows XP Service Pack 2-based computer (883356)


The information in this article applies to:

  • Microsoft Windows XP Home Edition Service Pack 2 (SP2)
  • Microsoft Windows XP Media Center Edition Service Pack 2 (SP2)
  • Microsoft Windows XP Professional Service Pack 2 (SP2)
  • Microsoft Windows XP Tablet PC Edition 2005
Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you try to install a serial modem or a universal serial bus (USB) modem on your Microsoft Windows XP Service Pack 2 (SP2)-based computer, you may receive the following error message:
Windows was unable to install the modem.

CAUSE

This problem occurs if there are no entries under the following Windows registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Modem

This problem may occur after you remove third-party modem software from your computer.

RESOLUTION

To resolve this problem, repopulate the subkey with the correct entries and values, as follows.

Subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Modem

Entry Name: ErrorControl
Type: REG_DWORD
Value: 0

Entry Name: Group
Type: REG_SZ
Value: Extended base

Entry Name: Start
Type: REG_DWORD
Value: 3

Entry Name: Tag
Type: REG_DWORD
Value: 4

Entry Name: Type
Type: REG_DWORD
Value: 1

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To add these entries to the subkey, follow these steps:
  1. Click Start, click Run, type regedit, and then click OK.
  2. Locate and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Modem

  3. On the Edit menu, point to New, and then click DWORD Value.
  4. Type ErrorControl, and then press ENTER.
  5. On the Edit menu, click Modify.
  6. Type 0, and then click OK.
  7. On the Edit menu, point to New, and then click String Value.
  8. Type Group, and then press ENTER.
  9. On the Edit menu, click Modify.
  10. Type Extended base, and then click OK.
  11. On the Edit menu, point to New, and then click DWORD Value.
  12. Type Start, and then press ENTER.
  13. On the Edit menu, click Modify.
  14. Type 3, and then click OK.
  15. On the Edit menu, point to New, and then click DWORD Value.
  16. Type Tag, and then press ENTER.
  17. On the Edit menu, click Modify.
  18. Type 4, and then click OK.
  19. On the Edit menu, point to New, and then click DWORD Value.
  20. Type Type, and then press ENTER.
  21. On the Edit menu, click Modify.
  22. Type 1, and then click OK.
  23. Quit Registy Editor.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Modification Type:MajorLast Reviewed:11/10/2004
Keywords:kbUpgrade kbprb kbConfig kbsettings kb3rdparty kbConsumer kbHardware kbDriver kbtshoot kbModem kbfix kbBug KB883356 kbAudEndUser kbAudITPRO
©2004 Microsoft Corporation. All rights reserved.