Computer randomly shutsdown

On a Windows 7 machine, when I run this code as a compiled program then the computer will randomly shutdown With an (Event ID 109 Kernel-Power) after 10 to 30 minutes. At the console a box pops up and says "The computer will shut down in less than a minute." This is not a crash. The computer knows it is going down. Warns the user and writes an event to the event log.

If I do not run this compiled code then the system stays up all day. If I start the program again, within a 10 to 30 minutes the computer will shut down.

On the XP machine there is no problem with shutting down.

My Code

;Opt("WinTitleMatchMode" ,2)
#include <Array.au3>
Opt("TrayIconHide", 1)
sleep(5000)
Global $_State
Global $_pos[2] =[0,0]
Global $_size[2] =[0,0]


While 1
$_pos[0] = 1
$_pos[1] = 1
$_size[0] = 1
$_size[1] = 1
$_State = WinGetState("[CLASS:IEFrame]","")
  if $_State = 0 Then
   _Open()
  else
   $_pos = WinGetPos("[CLASS:IEFrame]")
   $_size = WinGetClientSize("[CLASS:IEFrame]")
   if $_size[0]  < 1280 then _Resize()
   if $_size[1]  < 1024 then _Resize()
   ; msgbox(1,"pos",$_pos[0] & @CRLF & $_pos[1],5)
   if $_pos[0] <> 0 then  _Resize()
   if $_pos[1] <> 0 then  _Resize()
  EndIf
Sleep(5000)
Wend

Func _Open()
if FileExists("C:\Program Files (x86)\Internet Explorer\iexplore.exe") then
  $_IE = Run("C:\Program Files (x86)\Internet Explorer\iexplore.exe")
Else
  $_IE = Run("C:\Program Files\Internet Explorer\iexplore.exe")
  Endif
Sleep(2000)
EndFunc

Func _Resize()
WinActivate("[CLASS:IEFrame]")
WinMove("[CLASS:IEFrame]", "", 0, 0, 1280, 1024)
EndFunc

This code functions exactly as it should, other than the unexplained shut down. As you can see there is nothing in my code to shut down the system. I don't see any run away loops or memory/cpu hogs. I can only figure that I've stumbled into a bug.

Event ID 109 Kernel Power

Log Name:	  System
Source:		Microsoft-Windows-Kernel-Power
Date:		  10/10/2009 12:10:00 PM
Event ID:	  109
Task Category: (103)
Level:		 Information
Keywords:	  (4)
User:		  N/A
Computer:	  Fred
Description:
The kernel power manager has initiated a shutdown transition.
Event Xml:
<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>109</EventID>
	<Version>0</Version>
	<Level>4</Level>
	<Task>103</Task>
	<Opcode>0</Opcode>
	<Keywords>0x8000000000000004</Keywords>
	<TimeCreated SystemTime="2009-10-10T16:10:00.925187500Z" />
	<EventRecordID>5385</EventRecordID>
	<Correlation />
	<Execution ProcessID="428" ThreadID="432" />
	<Channel>System</Channel>
	<Computer>Fred</Computer>
	<Security />
  </System>
  <EventData>
	<Data Name="ShutdownActionType">6</Data>
	<Data Name="ShutdownEventCode">0</Data>
	<Data Name="ShutdownReason">0</Data>
  </EventData>
</Event>