The system has rebooted without cleanly shutting down firs

I have had Windows 8 Pro installed for over a month now. During that time I have never turned the power off without "Shutting" the system off. I have never had the system reboot unexpectedly. So I am wondering why I sometimes (quite often) see a Critical error in my System event log. The Event ID is 41. The text of the error message is as follows.

"The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly."

In the details window, XML view is this:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>41</EventID>
<Version>3</Version>
<Level>1</Level>
<Task>63</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000002</Keywords>
<TimeCreated SystemTime="2012-12-03T14:27:10.965793300Z" />
<EventRecordID>3136</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="8" />
<Channel>System</Channel>
<Computer>Walts_64bit</Computer>
<Security UserID="S-1-5-18" />
</System>
- <EventData>
<Data Name="BugcheckCode">0</Data>
<Data Name="BugcheckParameter1">0x0</Data>
<Data Name="BugcheckParameter2">0x0</Data>
<Data Name="BugcheckParameter3">0x0</Data>
<Data Name="BugcheckParameter4">0x0</Data>
<Data Name="SleepInProgress">6</Data>
<Data Name="PowerButtonTimestamp">0</Data>
<Data Name="BootAppStatus">3221226513</Data>
</EventData>
</Event

Whenever I get this Critical error, a little earlier in the System event log is another error. The text of which is as follows.

"The previous system shutdown at 9:15:07 PM on ?12/?2/?2012 was unexpected."

And in the Details window/XML View is this text:

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="EventLog" />
<EventID Qualifiers="32768">6008</EventID>
<Level>2</Level>
<Task>0</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-12-03T14:27:20.000000000Z" />
<EventRecordID>3127</EventRecordID>
<Channel>System</Channel>
<Computer>Walts_64bit</Computer>
<Security />
</System>
- <EventData>
<Data>9:15:07 PM</Data>
<Data>?12/?2/?2012</Data>
<Data />
<Data />
<Data>40859</Data>
<Data />
<Data />

Can anyone help me with these errors? Remember, the sys has NEVER rebooted by it's self, and I ALWAYS shut it down by the Charms Bar Power Shutdown button.

Any help would be appreciated.
Walt