windows 7 random reboot even at idle

hi i have been getting random reboots recently ive updated my bios thinking that would maybe fix it but did not the reboot seems be random i ran a stability test for 5 hours and no crash then opened up a folder and bam reboot not sure exactly what i can do any help would be great.


- <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>2</Version>

<Level>1</Level>

<Task>63</Task>

<Opcode>0</Opcode>

<Keywords>0x8000000000000002</Keywords>

<TimeCreated SystemTime="2014-05-04T12:39:48.980404300Z" />

<EventRecordID>4143</EventRecordID>

<Correlation />

<Execution ProcessID="4" ThreadID="8" />

<Channel>System</Channel>

<Computer>Mongo</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">false</Data>

<Data Name="PowerButtonTimestamp">0</Data>

</EventData>


</Event>

i read somewhere where it was a windows 7 error in pro and enterprise so i put win7 ultimate on and all was well for a few hours then it started again the system if around 8 months old