I'm experiencing lots of computer restarts (occasionally at very bad times, e.g. during a support call with a client).

Digging into the Event logs gives me lots of Critical Kernel-Power errors:

Critical Kernel-Power log messages in Event Viewer

The details (in XML-view) of a particular log are:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" /> 
  <TimeCreated SystemTime="2014-08-04T07:20:55.270411900Z" /> 
  <Correlation /> 
  <Execution ProcessID="4" ThreadID="8" /> 
  <Security UserID="S-1-5-18" /> 
  <Data Name="BugcheckCode">126</Data> 
  <Data Name="BugcheckParameter1">0xffffffffc0000005</Data> 
  <Data Name="BugcheckParameter2">0xfffff88001bc2d6e</Data> 
  <Data Name="BugcheckParameter3">0xfffff880075e7908</Data> 
  <Data Name="BugcheckParameter4">0xfffff880075e7160</Data> 
  <Data Name="SleepInProgress">false</Data> 
  <Data Name="PowerButtonTimestamp">0</Data> 

Sometimes i see a Bug check code of zero (which implies it fits with this MSDN scenario), but typically, i see what's shown above: a bug check code of 126, or 0x7E.

i suspect my Power Supply is getting flaky on me because of various related posts around the web and because the machine is almost six years old, but the bug check code of 126 points to unhandled system thread exceptions. Am i barking up the wrong tree?

Is my issue a bad power supply or something else? Why is my computer restarting? Is there a way for me to figure out what's causing my 126 bug check code and unhandled thread exception?

These errors seem to be increasing in frequency, too.

Update: More information

A cross-section of errors leading up to one of these restarts involves something like the following:

Log file output showing Disk-related errors leading up to a Critical error.

The Disk errors give a message of:

The driver detected a controller error on \Device\Harddisk3\DR3.

Could my hard drive be failing and take down the machine? Seems unlikely (but what do i know?) because there are lots of those errors further down in the logs that don't lead into a reboot.

The Service Control manager error is a service pointing to an exe i removed from the machine a week ago, but didn't uninstall the service. The IIS error is the Application Host Helper Service looking for C:\inetpub\history which doesn't exist on my machine. These two errors seem unrelated as well.

  • 1
    You need to start to elminate the possible causes. The replacement of a PSU would be the cheapest place to start. – Ramhound Aug 4 '14 at 15:45
  • That PSU could then become the first part of a new PC ;-) – Hannu Aug 4 '14 at 15:48
  • 1
    What are the log entries before the Kernel-Power? Those log entries generally are just saying the system rebooted. Think of them more like a symptom than the cause . . . – ernie Aug 4 '14 at 16:51
  • @Hannu my thoughts exactly! :) – jrsconfitto Aug 4 '14 at 17:27
  • @ernie i've added the log entries before the error, i'm not seeing anything that sticks out as a cause... except maybe the disk errors? – jrsconfitto Aug 4 '14 at 17:42
up vote 4 down vote accepted

Looks to me like your PSU is going bad. It's possible that you're seeing various errors from components (such as your HDD) because they are losing power abruptly.

For example, I had a PSU a while ago that was sending out very unreliable power through the +12V rail. This was leading to the motors in the HDD to lose power, and slow down, only to speed right back up. Now, in my case, the computer wasn't crashing completely. But, if your PSU is fluctuating enough, it very well could be failing to send enough power when it's requested.

  • 1
    Is there an easy way to monitor the PSU for misbehavior? (and do it cheaply?) i'm guessing not. – jrsconfitto Aug 12 '14 at 15:18
  • Yup! HWMonitor should show you voltages. cpuid.com/softwares/hwmonitor.html – IAmTheSquidward Aug 12 '14 at 15:29
  • It's the PSU, this weekend i have to attend some issues with the same problems and events, the change of the PSU fixed the issues. Use hirens boot cd/USB for test yoyr devices as memory OR the hdds but it seems a PSU failure. – n00b Aug 12 '14 at 16:52

The disk controller-related errors you mentioned are a classic sign of imminent hard drive failure. It could be (as others have mentioned) that your PSU is failing and causing the other problems, or it could actually be disk failure.

Either way, I wouldn't keep this PC running in this state long.

  1. Swap out the PSU with one from a good manufacturer. This is your cheapest fix, if it works.
  2. On another machine, download the disk diagnostic tool provided by the manufacturer of your hard drive and burn it to a CD. Run the diagnostics and see if the disk is okay.
  3. Watch the event log for those critical Disk errors. If they (or the reboots) continue, try a different cable, SATA port, and hard drive in that order. (It's super rare, but every once in a while a bad cable can muck things up.)

Good luck!

This Event could occur mainly due to following two reasons:

  1. The computer restarts, and there is a Stop error BugcheckCode in the event data.
  2. The computer is shut down by pressing and holding the power button

Its solution is best provided by the Microsoft Support

  • 2
    You're describing the exact event i describe in my question, but i'm asking for why this event happens. Also, my question already links to the exact support article you link to in your answer. Is there something specific that you're pointing out that i originally missed? – jrsconfitto Aug 16 '14 at 1:54

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