DOCUMENT:Q247886 08-MAY-2002 [winnt] TITLE :Computer Stops Responding to Mouse or Keyboard Input PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kbWinNT400PreSP7Fixkbfixlist ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 - Microsoft Windows NT Workstation version 4.0 ------------------------------------------------------------------------------- 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 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.