PS/2 Keyboard/Mouse Not Recognized When Plugged Into Running Computer

View products that this article applies to.

This article was previously published under Q262798

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SYMPTOMS

If a PS/2-style keyboard and/or Mouse is not connected to the computer before Windows 2000 startup, the keyboard is not recognized if you connect it later.

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RESOLUTION

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 (http://support.microsoft.com/kb/260910/EN-US/ ) How to Obtain the Latest Windows 2000 Service Pack

The English version of this fix should have the following file attributes or later:

   Date         Time       Version         Size     File name
   -------------------------------------------------------------
   02/04/2002   10:19 AM   5.0.2195.4900   48,720   i8042prt.sys

When you install this hotfix by using the hotfix package, the following registry items are created and set to add "hotplugging" capability:

Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\Parameters
Value: Headless
Type: REG_DWORD
Data: 0x1 (Allow hotplugging a PS/2-style keyboard. To disable this feature, set the data value to 0.)

This hotfix was updated on 2/4/2002. The updated hotfix also prevents the following error messages from appearing in the event log when you detach a USB keyboard:

Type: Warning
Source: i8042prt
Event: 32
Description: The keyboard device does not exist or was not detected.
Type: Error
Source: i8042prt
Event: 26
Description: Exceeded the allowable number of retries (configurable via the registry) on device.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows

If you need to log the error messages, change the value of the ReportResetErrors value in the following registry key to 1:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\Parameters

NOTE: This feature is highly dependent on the computer's BIOS. Because PS/2 hotplug is not in the PS/2 specification, some PS/2 controllers may not correctly handle "hotplugging" of a device, and some may short out devices. This new driver does nothing special to accommodate hotplug other than ignore initialization errors.

NOTE: This hotfix also corrects a problem that causes the operating system to stop responding on a Dell PE2550, which uses a USB keyboard.

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 3.

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MORE INFORMATION

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 (http://support.microsoft.com/kb/265173/EN-US/ ) The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 (http://support.microsoft.com/kb/296861/EN-US/ ) Use QChain.exe to Install Multiple Hotfixes with One Reboot

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