Microsoft KB Archive/247886

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Computer Stops Responding to Mouse or Keyboard Input

Article ID: 247886

Article Last Modified on 11/1/2006


  • Microsoft Windows NT Server 4.0 Standard Edition
  • Microsoft Windows NT Workstation 4.0 Developer Edition

This article was previously published under Q247886


While you are using your Windows NT 4.0-based computer, it may stop responding to mouse or keyboard input. If you use the Task Manager tool to view the current processes that are running on your computer, you may observe that the Central Processing Unit (CPU) usage is at or near 100 percent. Also, the "% Processor Time" and "Priority Current" counters in the Performance Monitor tool Thread object may indicate that a thread has a higher priority (and is subsequently using more CPU time) than was expected.


This problem can occur when the NtSetInformationThread() function does not check threads properly before granting them a priority. This allows a thread to acquire HIGH_PRIORITY (or level above LOW_REALTIME_PRIORITY) and access to privileged mode with unlimited access to the CPU.


A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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

   Date         Time     Size        File name      Platform
   10/25/1999   04:54p     952,192   Ntkrnlmp.exe     x86
   10/25/1999   04:53p     932,032   Ntoskrnl.exe     x86
   10/25/1999   04:52p   1,405,184   Ntkrnlmp.exe   Alpha
   10/25/1999   04:51p   1,376,896   Ntoskrnl.exe   Alpha


Microsoft has confirmed that this is a problem in Windows NT 4.0.

Keywords: kbhotfixserver kbqfe kbfix kbprb KB247886