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Q247886: Computer Stops Responding to Mouse or Keyboard Input

Article: Q247886
Product(s): Microsoft Windows NT
Version(s): winnt:4.0
Operating System(s): 
Keyword(s): kbWinNT400PreSP7Fixkbfixlist
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 
- Microsoft Windows NT Workstation version 4.0 
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SYMPTOMS
========

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.

CAUSE
=====

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.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems 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 on support costs, please go to the following address on the World
Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal 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



STATUS
======

Microsoft has confirmed this to be a problem in Windows NT 4.0.

Additional query words:

======================================================================
Keywords          : kbWinNT400PreSP7Fix kbfixlist
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbprb
Solution Type     : kbfix

=============================================================================

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