PC will not start up sometimes (minidump/power off), BSOD, Win 7 x64

Event[33474]:
Log Name: System
Source: Microsoft-Windows-Kernel-Power
Date: 2013-02-23T07:18:33.004
Event ID: 86
Task: N/A
Level: Error
Opcode: Info
Keyword: N/A
User: N/A
User Name: N/A
Computer: AMD-PC
Description:
The system was shut down due to a critical thermal event.
Shutdown Time = ?2013?-?02?-?23T14:18:33.004828800Z
ACPI Thermal Zone = ACPI\ThermalZone\THRM
_CRT = 273K

Is the computer hot? Report us the heat of the computer after a couple of hours of your normal usage. Upload a screenshot of the summery tab of Speccy.

Check if the Power Supply Unit (PSU) supplying adequate power to the computer or not.
eXtreme Power Supply Calculator
At least 30% extra is safe.

Code:

BUGCHECK_STR:  0xc00002e3

ERROR_CODE: (NTSTATUS) 0xc00002e3 - Security Accounts Manager initialization failed because of the following error:  %hs  Error Status: 0x%x.  Please click OK to shutdown this system and reboot into Safe Mode, check the event log for more detailed information.

EXCEPTION_CODE: (NTSTATUS) 0xc00002e3 - Security Accounts Manager initialization failed because of the following error:  %hs  Error Status: 0x%x.  Please click OK to shutdown this system and reboot into Safe Mode, check the event log for more detailed information.

EXCEPTION_PARAMETER1:  fffff8a00144c490

EXCEPTION_PARAMETER2:  ffffffffc0000189

EXCEPTION_PARAMETER3:  0000000000000000

EXCEPTION_PARAMETER4: 0

CUSTOMER_CRASH_COUNT:  1

We need to do some tests here. Uninstall Avast using Avast Uninstall Utility. Use Microsoft Security Essentials as your antivirus with windows inbuilt firewall, and free MBAM as the on demand scanner.
Download, install and update those, and then run full system scans with both of them, one by one. Also Scan the system for possible virus infection with the following programs, too.

• Anti-rootkit utility TDSSKiller
• Windows Defender Offline

Free up the startup. Windows does not need any other program to auto start with it, but the auto start programs often conflicts and causes various problems including BSODs.

1. Click on the Start button
2. Type “msconfig (without quotes), click the resulting link. It will open the System Configuration window.
3. Select the “Startup” tab.
4. Deselect all items other than the antivirus.
5. Apply > OK
6. Accept then restart.

Uninstall these factory bloatware.

Code:

Start Menu\Programs\ASUS Utility 
Start Menu\Programs\Foxconn 
Start Menu\Programs\Foxconn\Fox DMI  
Start Menu\Programs\Foxconn\Fox Logo 
Start Menu\Programs\Foxconn\FOX ONE 
Start Menu\Programs\Foxconn\LiveUpdate

Stress test the Graphics Card using Furmark.
Video Card - Stress Test with Furmark

Test your RAM modules for possible errors.
How to Test and Diagnose RAM Issues with Memtest86+
Run memtest for at least 8 passes, preferably overnight.

Stress test the CPU.
Hardware - Stress Test With Prime95

Let us know the results. _______________________________________________________________________
BSOD ANALYSIS:

Code:

*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************

Use !analyze -v to get detailed debugging information.

BugCheck C00002E3, {fffff8a00144c490, ffffffffc0000189, 0, 0}

Probably caused by : ntkrnlmp.exe ( nt!ExpSystemErrorHandler2+5e1 )

Followup: MachineOwner
---------

0: kd> !analyze -v
*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************

Unknown bugcheck code (c00002e3)
Unknown bugcheck description
Arguments:
Arg1: fffff8a00144c490
Arg2: ffffffffc0000189
Arg3: 0000000000000000
Arg4: 0000000000000000

Debugging Details:
------------------


BUGCHECK_STR:  0xc00002e3

ERROR_CODE: (NTSTATUS) 0xc00002e3 - Security Accounts Manager initialization failed because of the following error:  %hs  Error Status: 0x%x.  Please click OK to shutdown this system and reboot into Safe Mode, check the event log for more detailed information.

EXCEPTION_CODE: (NTSTATUS) 0xc00002e3 - Security Accounts Manager initialization failed because of the following error:  %hs  Error Status: 0x%x.  Please click OK to shutdown this system and reboot into Safe Mode, check the event log for more detailed information.

EXCEPTION_PARAMETER1:  fffff8a00144c490

EXCEPTION_PARAMETER2:  ffffffffc0000189

EXCEPTION_PARAMETER3:  0000000000000000

EXCEPTION_PARAMETER4: 0

CUSTOMER_CRASH_COUNT:  1

DEFAULT_BUCKET_ID:  WIN7_DRIVER_FAULT

PROCESS_NAME:  lsass.exe

CURRENT_IRQL:  0

LAST_CONTROL_TRANSFER:  from fffff8000333868e to fffff80002ed6c40

STACK_TEXT:  
fffff880`062e04e8 fffff800`0333868e : 00000000`0000004c 00000000`c00002e3 fffff880`062e0608 fffffa80`06d03810 : nt!KeBugCheckEx
fffff880`062e04f0 fffff800`03126311 : fffffa80`06d38be1 fffff880`062e0ca0 00000000`00000100 fffffa80`06d0ce00 : nt!PoShutdownBugCheck+0xae
fffff880`062e0570 fffff800`02f229cd : 00000000`00000000 00000000`00000002 00000000`00000000 00000000`0013f601 : nt!ExpSystemErrorHandler2+0x5e1
fffff880`062e07a0 fffff800`0330b2e1 : 00000000`c00002e3 00000000`00000002 00000000`00000001 fffff880`062e0b58 : nt!ExpSystemErrorHandler+0xdd
fffff880`062e07e0 fffff800`0330d063 : 00000000`c00002e3 fffffa80`00000002 fffff8a0`00000001 fffff880`062e0b58 : nt!ExpRaiseHardError+0xe1
fffff880`062e0b10 fffff800`02ed5ed3 : fffffa80`06d2a590 00000000`00000001 00000000`0013f598 fffff800`031d1734 : nt!NtRaiseHardError+0x1a1
fffff880`062e0bb0 00000000`774d264a : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiSystemServiceCopyEnd+0x13
00000000`0013f578 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : 0x774d264a


STACK_COMMAND:  kb

FOLLOWUP_IP: 
nt!ExpSystemErrorHandler2+5e1
fffff800`03126311 cc              int     3

SYMBOL_STACK_INDEX:  2

SYMBOL_NAME:  nt!ExpSystemErrorHandler2+5e1

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: nt

IMAGE_NAME:  ntkrnlmp.exe

DEBUG_FLR_IMAGE_TIMESTAMP:  50e79935

FAILURE_BUCKET_ID:  X64_0xc00002e3_nt!ExpSystemErrorHandler2+5e1

BUCKET_ID:  X64_0xc00002e3_nt!ExpSystemErrorHandler2+5e1

Followup: MachineOwner
---------

Had I been there, I would have changed the PSU.

When you do the stress tests, keep a close watch on your CPU temps and GPU temps. Shut the test down if the temps go too high. I use Core Temp for the CPU. If I am not mistaken, your GPU is on the CPU so I'm not sure how the temps work with that. I would assume they are pretty much one in the same. But MSI Afterburner is a good program for GPU temps. But, your bug check indicated a thermal event, meaning the computer shut down due to over heating. I would think in that event it would be wise to monitor your temps before running the stress tests to get a base line of what is normal. If you are shutting down due to heat during normal usage, a stess test will be too much for your machine to handle, probably. Let's see what your normal temps are.

Did you assemble this PC yourself?
What did you use for thermal paste on the CPU, and how did you apply it?
Are you using a stock CPU fan that came with the processor or something else?