When you install update 938371 from Windows Update, you may lose access to the USB mouse or the USB keyboard on a computer that is running Windows Vista

When you install update 938371 from Windows Update, you may lose access to the USB mouse or the USB keyboard on a computer that is running Windows Vista.

Notes

• This problem occurs when a very specific chain of events occurs in a specific order. This problem is not common. But when this problem occurs, it is very difficult to troubleshoot because you may lose access to the mouse and the keyboard. And, such access is required to troubleshoot the problem.
• See the "Advanced Troubleshooting" section for more information about the conditions in which this problem is known to occur and about the cause of the problem.

Before you begin

Make sure that you have one of the following items:

• A mouse with a PS/2 plug
• A keyboard with a PS/2 plug

Also, the computer must have a PS/2 port to use most of the methods. If the computer does not have a PS/2 port, see the "Advanced troubleshooting" section.

Depending on what kind of mouse or keyboard that you have, use one of the following methods:

• If you have both a PS/2 mouse and a PS/2 keyboard, and the computer has two PS/2 ports, use Method 1.
• If you only have a PS/2 mouse, and the computer has a PS/2 port, use Method 2.
• If you only have a PS/2 keyboard, and the computer has a PS/2 port, use Method 3.

If you do not have a PS/2 mouse or a PS/2 keyboard, or the computer does not have a PS/2 port, see the "Advanced Troubleshooting" section.

Do you have a PS/2 mouse or a PS/2 keyboard?

A PS/2 mouse and a PS/2 keyboard plug into the computer by using a different hardware connection than a USB connection. The PS/2 plug is an older hardware connection that is supported on some USB mouse devices, USB keyboards, and computers.

If the USB mouse or keyboard that you are using has a PS/2 plug, you see a small, round plug that has six pins.

If the USB mouse or USB keyboard does not have a PS/2 plug, you have to obtain a PS/2 mouse or a PS/2 keyboard to use methods 1 through 5.

If you do not have a PS/2 mouse or a PS/2 keyboard, see the "Advanced Troubleshooting" section.

Does the computer have a PS/2 port?

A PS/2 port is a small, round connection that has six small holes. In comparison, a USB connection is rectangular.

In most cases, a PS/2 mouse port on a computer is green, and a PS/2 keyboard port is purple. Some mobile PCs have a single PS/2 port that supports both a mouse and a keyboard.

If the computer does not have a PS/2 port, see the "Advanced Troubleshooting" part.

Methods to resolve the problem

Use the following preferred methods in the order in which they are listed to resolve the problem. You may be unable to use one or more of these methods. The appropriate method depends on your unique situation.

If the following methods do not resolve the problem, you can try the methods in the "Methods to resolve the problem for advanced users" section, or you can contact Microsoft for free support for this problem.

Method 1

Plug in a PS/2 mouse and a PS/2 keyboard, and perform a system restore to remove update 938371.

Before you begin

Make sure that you have the following items:

• A system restore point that was saved before update 938371 was installed. If you follow these steps, and you discover that you do not have such a system restore point, this method will not work.
  
  Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed, use a system restore point that is earlier than April 8, 2008.
• A PS/2 mouse and a PS/2 keyboard.

To use System Restore to remove update 938371, follow these steps:

1. Turn off the computer.
2. Plug in the PS/2 mouse and the PS/2 keyboard.
3. Restart the computer. If it is necessary, log on to the computer by using your user account.
4. Click Start, and then type rstrui in the Start Search box.
5. In the Programs list, click rstrui.exe.
   If you are prompted for an administrator password or for a confirmation, enter the password, or click Continue.
6. In the Restore system files and settings page, click Choose a different restore point, and then click Next.
7. In the Choose a restore point page, click to select a system restore point that was saved before update 938371 was installed.
   
   Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed, use a system restore point that is earlier than April 8, 2008.
8. Click Next.
9. Verify the restore point that you want to use, and then click Finish.
10. After you have restored the system, you can restart the computer and plug in the USB mouse and keyboard.

If the problem is resolved, go to the "How to prevent update 938371 from installing after you have resolved the problem" section.

Method 2

Plug in a PS/2 mouse, and perform a system restore to remove update 938371.

Before you begin

Make sure that you have the following items:

• A system restore point that was saved before update 938371 was installed. If you follow these steps, and you discover that you do not have such a system restore point, this method will not work.
  
  Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed, use a system restore point that is earlier than April 8, 2008.
• A PS/2 mouse.

Note If your user account requires you to enter a password to log on, you must enable the Windows On-Screen Keyboard at the Windows Welcome screen. You must have access to the On-Screen Keyboard to enter your password by using the mouse.

To use System Restore to remove update 938371, follow these steps:

1. Turn off the computer.
2. Plug in the PS/2 mouse.
3. Restart the computer. If it is necessary, log on to the computer.
   
   Note If you have to use the CTRL+ALT+DELETE keyboard shortcut to log on, follow these steps:
   1. Click the Ease of Access icon on the lower-left side of the Windows Welcome screen.
   2. Select the Use the computer without a keyboard check box, and then click OK.
   3. In the On-Screen Keyboard, click the following keys in the order in which they are listed, and then click Enter:
      • CTRL
      • ALT
      • DELETE
   4. If you are prompted for a password, enter your password by using the On-Screen Keyboard, and then click ENTER.
4. Click Start, click All Programs, click Accessories, click System Tools, and then click System Restore.
5. In the Restore system files and settings page, click Choose a different restore point, and then click Next.
6. In the Choose a restore point page, click to select a system restore point that was saved before update 938371 was installed.
   
   Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed, use a system restore point that is earlier than April 8, 2008.
7. Click Next.
8. Verify the restore point that you want to use, and then click Finish.
9. After you have restored the system, restart the computer, and plug in the USB mouse and keyboard.

If the problem is resolved, go to the "How to prevent update 938371 from installing after you have resolved the problem" section.

Method 3

Plug in a PS/2 keyboard, and perform a system restore to remove update 938371.

Before you begin

Make sure that you have the following items:

• A system restore point that was saved before update 938371 was installed. If you follow these steps, and you discover that you do not have such a system restore point, this method will not work.
  
  Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed, use a system restore point that is earlier than April 8, 2008.
• A PS/2 keyboard.

To use System Restore to remove update 938371, follow these steps:

1. Turn off the computer.
2. Plug in the PS/2 keyboard.
3. Restart the computer.
4. Log on to the computer.
5. Use the following keyboard shortcut:
   Windows logo key+R
6. In the Open box, enter the following text, and then press ENTER:
   rstrui
   If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
7. In the Restore system files and settings page, click Choose a different restore point, and then click Next.
8. In the Choose a restore point window, use the arrow keys on the keyboard to select a system restore point that was saved before update 938371 was installed.
   
   Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed on the computer, use a system restore point that is earlier than April 8, 2008.
9. Use the following keyboard shortcut:
   ALT+N
10. Verify the restore point that you want to use, and then press ENTER.
11. After you have restored the system, you can restart the computer and plug in the USB mouse and keyboard.

If the problem is resolved, go to the "How to prevent update 938371 from installing after you have resolved the problem" section.

Methods to resolve the problem for advanced users

Method 4

Plug in a USB keyboard, and then perform an offline System Restore by using a Windows Vista DVD.

Notes

• To use this method, you must have the following items:
  • A Windows Vista DVD
  • A PS/2 mouse
  • A USB keyboard
    
    Note This USB keyboard is required only for the initial steps of this method. A USB keyboard will still work during these initial steps.
• To use this method, the computer must be configured to start from the DVD drive. In some cases, you may have to modify the BIOS settings on the computer to configure the computer to start from the DVD drive. For more information about how to configure the computer to start from the DVD drive, see the manufacturer documentation, or contact the computer manufacturer.

To use an offline System Restore to remove Update 938371, follow these steps:

1. Insert the Windows Vista DVD, and then restart the computer.
2. Plug in the USB keyboard and the PS/2 mouse.
   Note The USB keyboard will work until the Windows logon screen appears.
3. When you receive the following message, press any key:
   Press any key to boot from CD or DVD.
4. Set the following preferences, and then click Next:
   • Language to install
   • Time and currency format
   • Keyboard or input method
5. Click Repair your computer, select the operating system that you want to repair if that option is available, and then click Next.
6. Click System Restore, and then click Next.
7. Click to select a restore point that occurs before the installation date of update 938371.
   
   Note Update 938371 was released on April 8, 2008. If you do not know when update 938371 was installed on the computer, use a system restore point that is earlier than April 8, 2008.
8. Confirm the disks that you want to restore, and then click Next.
9. Click Finish, and then click Yes when you are prompted.
10. When the System Restore process is complete, click Restart to restart the computer.
11. Plug in the USB mouse.
12. After the computer restarts, click Close to confirm that the System Restore process has finished successfully.

Method 5

Plug in a PS/2 keyboard, and then copy the missing driver files from the Windows operating system or from Windows Recovery Environment (WinRE). To do this, you must start the computer from the Windows Vista DVD.

Notes

• To use this method, you must have the following items:
  • A Windows Vista DVD
  • A PS/2 keyboard
• To use this method, the computer must be configured to start from the DVD drive. In some cases, you may have to modify the BIOS settings on the computer to configure the computer to start from the DVD drive. For more information about how to configure the computer to start from the DVD drive, see the manufacturer documentation, or contact the computer manufacturer.

To use this method, you must search the driver store for the most recent backup of both the Msmouse.inf file and of the Keyboard.inf file, and then you must copy these files to the appropriate location. To do this, follow these steps:

1. Open an elevated command prompt. To do this, use one of the following methods:
   
   
   Method 1
   1. Turn off the computer.
   2. Plug in the PS/2 keyboard.
   3. Restart the computer.
   4. Log on to the computer.
   5. Use the following keyboard shortcut:
      Windows logo key+R
   6. In the Open box, type the following text, and then press ENTER:
      cmd
      If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
   Method 2
   1. Insert the Windows Vista DVD, and then restart the computer.
   2. Plug in the USB keyboard and the PS/2 mouse.
      
      Note The USB keyboard will work until the Windows logon screen appears.
   3. When you receive the following message, press any key:
      Press any key to boot from CD or DVD.
   4. Select the following preferences, and then click Next:
      • Language to install
      • Time and currency format
      • Keyboard or input method
   5. Click Repair your computer, select the operating system that you want to repair if that option is available, and then click Next.
   6. Under Choose a recovery tool, click Command Prompt.
2. To change to the \windows\system32\driverstore\filerepository folder, type the following command, and then press ENTER:
   CD \Windows\System32\DriverStore\FileRepository
3. Type the following command, and then press ENTER:
   dir msmouse.inf /s
4. The results may resemble the following:

   Directory of C:\Windows\System32\DriverStore\FileRepository\msmouse.inf_3dfa3917
   11/01/2006  11:33 PM            56,342 msmouse.inf
   1 File(s)         56,342 bytes
   
    Directory of C:\Windows\System32\DriverStore\FileRepository\msmouse.inf_8b7c4328
   1/20/2008  07:22 PM            56,562 msmouse.inf
   1 File(s)         56,562 bytes
   
    Directory of C:\Windows\System32\DriverStore\FileRepository\msmouse.inf_f4514c17
   01/20/2008  07:09 PM            56,342 msmouse.inf
   1 File(s)         56,342 bytes
   

5. Locate the most recent version of the Msmouse.inf file by examining the date stamp that is listed in the search results in step 4.
6. Type the following command, use the path of the most recent file that you determined from the results in step 4, and then press ENTER. For example, you would use the following command, based on the search results in step 4:
   copy c:\windows\system32\driverstore\filerepository\msmouse.inf_8b7c4328\msmouse.inf c:\windows\inf
7. Repeat steps 3 through 6, and use keyboard.inf instead of msmouse.inf in the command in step 3
8. Exit the command prompt, and then restart the computer.
9. Plug in the USB mouse and keyboard.

How to prevent update 938371 from installing after you have resolved the problem

After you successfully use one of the troubleshooting methods that are described in this article, you may want to prevent update 938371 from installing automatically on your computer again. To do this, follow these steps:

1. Click Start, click All Programs, and then click Windows Update.
2. Click Check for Updates.
3. Click View Available Updates.
4. Locate update 938371, and then click to clear the check box next to this update.
5. Right-click this update, and then click Hide update.
6. Click OK.
7. When you are asked for confirmation, click Yes.

Advanced troubleshooting

The following methods are for advanced users. If you are not an advanced user, or you are not comfortable with advanced troubleshooting, you might want to contact Support for Windows Vista. For information about how to contact support, visit the following Microsoft Web site: The following advanced troubleshooting method is recommended for advanced users.

Advanced Method

Use Remote Assistance to perform a System Restore to remove update 938371.

Conditions where this problem occurs

This problem only occurs when the following conditions occur in the order in which they are listed:

1. Version 1.0 of update 938371 was installed on the computer after the update was released in Feb. 2008.
2. You restarted the computer, and you selected the Last Known Good Configuration option.
3. Version 2.0 of 938371 was installed on the computer after the update was released in April 2008.

Note This problem only occurs if you have installed version 1.0 of KB938371 as the first step. Version 1.0 was removed from the computer when version 2.0 was installed.

Information about the cause of the problem

Microsoft has identified a problem in driver servicing when the conditions that are described in the "Conditions where this problem occurs" section are true. This problem is caused when the Msmouse.inf file or the Keyboard.inf file was removed from the INF folder in the Windows Directory.

Contact us

If this problem is not resolved, unfortunately this content is unable to help you any further. So, you might want to ask someone for help, or you might want to visit the following Microsoft Web site:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.