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CPU utilization reaches 100 percent when you run programs after you install Windows XP Service Pack 2

Support for Windows XP has ended

Microsoft ended support for Windows XP on April 8, 2014. This change has affected your software updates and security options. Learn what this means for you and how to stay protected.

This article has been archived. It is offered "as is" and will no longer be updated.
When you run programs, CPU utilization reaches 100 percent. When CPU utilization reaches 100 percent, programs either run slowly or stop responding (hang).

Note To view CPU utilization, press CTRL+ALT+DEL, click Task Manager, and then click the Performance tab.

On multiprocessor computers, you may experience many context switches each second or many system calls each second.

These symptoms occur after you install Microsoft Windows XP Service Pack 2 (SP2).
This problem occurs because of the user interface code that is included in Windows XP SP2. The high CPU utilization is caused by the additional overhead that occurs when the IsWindow function is called by the user interface code.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


To apply this hotfix, you must have Windows XP SP2 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
   Date         Time   Version            Size    File name   --------------------------------------------------------------   30-Mar-2005  19:53  5.1.2600.2643     577,024  User32.dll          30-Mar-2005  01:30  5.1.2600.2643   1,836,544  Win32k.sys   
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the terms that are used to describe software updates, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates

Article ID: 890582 - Last Review: 12/09/2015 01:57:03 - Revision: 5.0

Microsoft Windows XP Professional, Microsoft Windows XP Home Edition

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