random restarts, no bsod

From the system event logs:

Code:

The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
- <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="2010-07-20T15:26:40.192411800Z" /> 
  <EventRecordID>3352</EventRecordID> 
  <Correlation /> 
  <Execution ProcessID="4" ThreadID="8" /> 
  <Channel>System</Channel> 
  <Computer>htpc-PC</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>


Session "Microsoft-Windows-Setup" stopped due to the following error: 0xC000000D
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
  <Provider Name="Microsoft-Windows-Kernel-EventTracing" Guid="{B675EC37-BDB6-4648-BC92-F3FDC74D3CA2}" /> 
  <EventID>3</EventID> 
  <Version>0</Version> 
  <Level>2</Level> 
  <Task>2</Task> 
  <Opcode>14</Opcode> 
  <Keywords>0x8000000000000010</Keywords> 
  <TimeCreated SystemTime="2010-07-20T15:26:41.705614500Z" /> 
  <EventRecordID>23</EventRecordID> 
  <Correlation /> 
  <Execution ProcessID="4" ThreadID="164" /> 
  <Channel>Microsoft-Windows-Kernel-EventTracing/Admin</Channel> 
  <Computer>htpc-PC</Computer> 
  <Security UserID="S-1-5-18" /> 
  </System>
- <EventData>
  <Data Name="SessionName">Microsoft-Windows-Setup</Data> 
  <Data Name="FileName">C:\Windows\Panther\setup.etl</Data> 
  <Data Name="ErrorCode">3221225485</Data> 
  <Data Name="LoggingMode">5</Data> 
  </EventData>
  </Event>

Is Windows 7 . . .Of course
- x86 (32-bit) or x64 ? x86
- the original installed OS on the system? Yes, brand new hardware. Clean install.
- What is the age of system (hardware)? NEW
- What is the age of OS installation A few times.

Specs:
Intel Core i3 530 Dual Core Processor Clarkdale LGA1156 2.93GHZ Hyperthreading 4MB Cache
Intel BOXDH55TC mATX Intel H55 LGA1156
OCZ OCZ3G1333LV4GK 4GB DDR3 2X2GB DDR3-1333 PC3-10666 CL 9-9-9-20 Dual Channel
Corsair VX450 450W ATX 12V 33A 24PIN ATX
Seagate Barracuda 7200.12 500GB SATA2 3.5IN 8.5MS 7200RPM 16MB H
Nmedia HTPC-5000B Desktop Media Centre Case mATX Black

- I have ran a few passes of memtest86, with no errors.
- I have monitored temperatures using CoreTemp and all are normal.
- I also noticed that when turning the computer on, or rebooting, it appears to struggle. The fans start spinning, then they stop. Then it tries again. Sometimes it takes up to 5 attempts for the computer powers up.

The only thing I suspect is that my RAM says 1.65V while my motherboard outputs 1.5V and is not changeable. I thought DDR3 RAM was all rated to 1.5V though?

Try a new PSU. PSU testers test voltage - but they don't tell you what happens when it's under load. And 450 watts just doesn't seem adequate to me (but that's just a guess on my part).

The PCI Serial port on your system is missing drivers. As this is a part of the chipset, I'd suggest checking Device Manager for problem devices.

Windows activation has failed several times.
Please do the following (this will not affect the analysis of the current files - but it may help later files that are acquired):
- activate/validate the Windows installation at Genuine Microsoft Software
- run sfc.exe /scannow to replace any problem files
- open a support incident with Microsoft to see if they can fix the activation issue
- If that doesn't fix it, then wipe the hard drive and reinstall Windows
- don't use "leaked"/torrent builds