BSOD suddenly after a few hours

Hello Peets, Welcome to SF

First off if your OCing in anyway stop, return everything to stock settings for the purposes of testing

If you havent already, fill in your system specs so we know what we are dealing with
System Info - See Your System Specs

Run some basic hardware tests
RAM - Test with Memtest86+
Disk Check (windows based check)
Hard Drive Diagnostic Procedure (bootable disk check)

Not sure what you have been doing and when so i just ran your last three dumps from today and they are all 0x1A memory management and as you have just put new ram in that has got to be the starting point, run memtest for multiple passes to see if any errors are found or take out new ram and see if crashes still happen

Looking at dump i can see all the ram is recognised but is it all compatible

Code:

*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************
Use !analyze -v to get detailed debugging information.
BugCheck 1A, {41790, fffffa8004c50c00, ffff, 0}
Probably caused by : ntkrnlmp.exe ( nt! ?? ::FNODOBFM::`string'+35054 )
Followup: MachineOwner
---------
7: kd> !analyze -v
*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************
MEMORY_MANAGEMENT (1a)
    # Any other values for parameter 1 must be individually examined.
Arguments:
Arg1: 0000000000041790, A page table page has been corrupted. On a 64 bit OS, parameter 2
 contains the address of the PFN for the corrupted page table page.
 On a 32 bit OS, parameter 2 contains a pointer to the number of used
 PTEs, and parameter 3 contains the number of used PTEs.
Arg2: fffffa8004c50c00
Arg3: 000000000000ffff
Arg4: 0000000000000000
Debugging Details:
------------------
 
BUGCHECK_STR:  0x1a_41790
CUSTOMER_CRASH_COUNT:  1
DEFAULT_BUCKET_ID:  WIN7_DRIVER_FAULT
PROCESS_NAME:  Steam.exe
CURRENT_IRQL:  0
LAST_CONTROL_TRANSFER:  from fffff80002f38b50 to fffff80002eccfc0
STACK_TEXT:  
fffff880`089d3718 fffff800`02f38b50 : 00000000`0000001a 00000000`00041790 fffffa80`04c50c00 00000000`0000ffff : nt!KeBugCheckEx
fffff880`089d3720 fffff800`02e9e281 : ffffffff`00000000 00000000`0522ffff fffffa80`00000000 fffffa80`0aa4d640 : nt! ?? ::FNODOBFM::`string'+0x35054
fffff880`089d38e0 fffff800`0319e65a : fffff8a0`03a6ea10 fffff880`089d3c20 00000000`00000000 fffffa80`0aa4d640 : nt!MmCleanProcessAddressSpace+0x679
fffff880`089d3930 fffff800`03181b7d : 00000000`40010004 fffff880`089d3b01 00000000`fff00000 fffffa80`0989d640 : nt!PspExitThread+0x56a
fffff880`089d3a30 fffff800`02ebfb3a : 00000000`00000001 fffff880`089d3ba8 00000000`00000001 00000000`00000000 : nt!PsExitSpecialApc+0x1d
fffff880`089d3a60 fffff800`02ebfe80 : 00000000`1619f848 fffff880`089d3ae0 fffff800`03181af0 00000000`00000001 : nt!KiDeliverApc+0x2ca
fffff880`089d3ae0 fffff800`02ecc2f7 : fffffa80`0aa4d640 00000000`fff00000 fffff880`000000c0 00000000`fff00000 : nt!KiInitiateUserApc+0x70
fffff880`089d3c20 00000000`77492c1a : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiSystemServiceExit+0x9c
00000000`13f0e7c8 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : 0x77492c1a
 
STACK_COMMAND:  kb
FOLLOWUP_IP: 
nt! ?? ::FNODOBFM::`string'+35054
fffff800`02f38b50 cc              int     3
SYMBOL_STACK_INDEX:  1
SYMBOL_NAME:  nt! ?? ::FNODOBFM::`string'+35054
FOLLOWUP_NAME:  MachineOwner
MODULE_NAME: nt
IMAGE_NAME:  ntkrnlmp.exe
DEBUG_FLR_IMAGE_TIMESTAMP:  503f82be
FAILURE_BUCKET_ID:  X64_0x1a_41790_nt!_??_::FNODOBFM::_string_+35054
BUCKET_ID:  X64_0x1a_41790_nt!_??_::FNODOBFM::_string_+35054
Followup: MachineOwner
---------
7: kd> !sysinfo cpuinfo
[CPU Information]
~MHz = REG_DWORD 2798
Component Information = REG_BINARY 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
Configuration Data = REG_FULL_RESOURCE_DESCRIPTOR ff,ff,ff,ff,ff,ff,ff,ff,0,0,0,0,0,0,0,0
Identifier = REG_SZ Intel64 Family 6 Model 30 Stepping 5
ProcessorNameString = REG_SZ Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz
Update Signature = REG_BINARY 0,0,0,0,4,0,0,0
Update Status = REG_DWORD 0
VendorIdentifier = REG_SZ GenuineIntel
MSR8B = REG_QWORD 400000000
Machine ID Information [From Smbios 2.4, DMIVersion 36, Size=1194]
BiosVendor = Award Software International, Inc.
BiosVersion = F3
BiosReleaseDate = 07/31/2009
SystemManufacturer = Gigabyte Technology Co., Ltd.
SystemProductName = P55-UD3
SystemFamily =  
SystemVersion =  
SystemSKU =  
BaseBoardManufacturer = Gigabyte Technology Co., Ltd.
BaseBoardProduct = P55-UD3
BaseBoardVersion = x.x
7: kd> !sysinfo cpumicrocode
Initial Microcode Version: 00000004:00000000
 Cached Microcode Version: 00000004:00000000
         Processor Family: 06
          Processor Model: 1e
       Processor Stepping: 05
7: kd> !sysinfo smbios
[SMBIOS Data Tables v2.4]
[DMI Version - 36]
[2.0 Calling Convention - No]
[Table Size - 1194 bytes]
[BIOS Information (Type 0) - Length 24 - Handle 0000h]
  Vendor                        Award Software International, Inc.
  BIOS Version                  F3
  BIOS Starting Address Segment e000
  BIOS Release Date             07/31/2009
  BIOS ROM Size                 200000
  BIOS Characteristics
       07: - PCI Supported
       09: - Plug and Play Supported
       11: - Upgradeable FLASH BIOS
       12: - BIOS Shadowing Supported
       15: - CD-Boot Supported
       16: - Selectable Boot Supported
       19: - EDD Supported
       22: - 360KB Floppy Supported
       23: - 1.2MB Floppy Supported
       24: - 720KB Floppy Supported
       25: - 2.88MB Floppy Supported
       26: - Print Screen Device Supported
       27: - Keyboard Services Supported
       28: - Serial Services Supported
       29: - Printer Services Supported
       30: - CGA/Mono Services Supported
  BIOS Characteristic Extensions
       00: - ACPI Supported
       01: - USB Legacy Supported
       04: - LS120-Boot Supported
       05: - ATAPI ZIP-Boot Supported
       08: - BIOS Boot Specification Supported
       10: - Specification Reserved
  BIOS Major Revision           255
  BIOS Minor Revision           255
  EC Firmware Major Revision    255
  EC Firmware Minor Revision    255
[System Information (Type 1) - Length 27 - Handle 0001h]
  Manufacturer                  Gigabyte Technology Co., Ltd.
  Product Name                  P55-UD3
  Version                        
  Serial Number                  
  UUID                          00000000-0000-0000-0000-000000000000
  Wakeup Type                   Power Switch
  SKUNumber                      
  Family                         
[BaseBoard Information (Type 2) - Length 8 - Handle 0002h]
  Manufacturer                  Gigabyte Technology Co., Ltd.
  Product                       P55-UD3
  Version                       x.x
  Serial Number                  
[System Enclosure (Type 3) - Length 17 - Handle 0003h]
  Manufacturer                  Gigabyte Technology Co., Ltd.
  Chassis Type                  Desktop
  Version                        
  Serial Number                  
  Asset Tag Number               
  Bootup State                  Unknown
  Power Supply State            Unknown
  Thermal State                 Unknown
  Security Status               Unknown
  OEM Defined                   0
[Processor Information (Type 4) - Length 35 - Handle 0004h]
  Socket Designation            Socket 1156
  Processor Type                Central Processor
  Processor Family              01h - Other
  Processor Manufacturer        Intel
  Processor ID                  e5060100fffbebbf
  Processor Version             Intel(R) Core(TM) i7 CPU
  Processor Voltage             8ah - 1.0V
  External Clock                133MHz
  Max Speed                     4000MHz
  Current Speed                 2800MHz
  Status                        Enabled Populated
  Processor Upgrade             Socket 478
  L1 Cache Handle               000ah
  L2 Cache Handle               000bh
  L3 Cache Handle               [Not Present]
  Serial Number                  
  Asset Tag Number               
  Part Number                    
[Memory Controller Information (Type 5) - Length 24 - Handle 0005h]
  Error Detecting Method        04h - 8-bit Parity
  Error Correcting Capability   04h - None 
  Supported Interleave          03h - One Way Interleave
  Current Interleave            03h - One Way Interleave
  Maximum Memory Module Size    0ah - 1024MB
  Supported Speeds              0001h - Other 
  Supported Memory Types        0001h - Other 
  Memory Module Voltage         5V 
  Number of Memory Slots        4
  Memory Slot Handle            0006h
  Memory Slot Handle            0007h
  Memory Slot Handle            0008h
  Memory Slot Handle            0009h
  Enabled Err Correcting Caps   04h - None 
[Memory Module Information (Type 6) - Length 12 - Handle 0006h]
  Socket Designation            A0
  Bank Connections              1fh - 1
  Current Speed                 31ns
  Current Memory Type           0001h - Other 
  Installed Size                0bh - 2048 [single bank]
  Enabled Size                  0bh - 2048 [single bank]
  Error Status                  00h - [No Errors] 
[Memory Module Information (Type 6) - Length 12 - Handle 0007h]
  Socket Designation            A1
  Bank Connections              2fh - 2
  Current Speed                 47ns
  Current Memory Type           0001h - Other 
  Installed Size                0bh - 2048 [single bank]
  Enabled Size                  0bh - 2048 [single bank]
  Error Status                  00h - [No Errors] 
[Memory Module Information (Type 6) - Length 12 - Handle 0008h]
  Socket Designation            A2
  Bank Connections              3fh - 3
  Current Speed                 63ns
  Current Memory Type           0001h - Other 
  Installed Size                0bh - 2048 [single bank]
  Enabled Size                  0bh - 2048 [single bank]
  Error Status                  00h - [No Errors] 
[Memory Module Information (Type 6) - Length 12 - Handle 0009h]
  Socket Designation            A3
  Bank Connections              4fh - 4
  Current Speed                 79ns
  Current Memory Type           0001h - Other 
  Installed Size                0bh - 2048 [single bank]
  Enabled Size                  0bh - 2048 [single bank]
  Error Status                  00h - [No Errors] 
[Cache Information (Type 7) - Length 19 - Handle 000ah]
  Socket Designation            Internal Cache
  Cache Configuration           0180h - WB Enabled Int NonSocketed L1
  Maximum Cache Size            0040h - 64K
  Installed Size                0040h - 64K
  Supported SRAM Type           0020h - Synchronous 
  Current SRAM Type             0020h - Synchronous 
  Cache Speed                   0ns
  Error Correction Type         Unknown
  System Cache Type             Unknown
  Associativity                 Unknown
[Cache Information (Type 7) - Length 19 - Handle 000bh]
  Socket Designation            External Cache
  Cache Configuration           0181h - WB Enabled Int NonSocketed L2
  Maximum Cache Size            0800h - 2048K
  Installed Size                2000h - 8192K
  Supported SRAM Type           0020h - Synchronous 
  Current SRAM Type             0020h - Synchronous 
  Cache Speed                   0ns
  Error Correction Type         Unknown
  System Cache Type             Unknown
  Associativity                 Unknown
[Physical Memory Array (Type 16) - Length 15 - Handle 001ah]
  Location                      03h - SystemBoard/Motherboard
  Use                           03h - System Memory
  Memory Error Correction       03h - None
  Maximum Capacity              33554432KB
  Memory Error Inf Handle       [Not Provided]
  Number of Memory Devices      4
[Memory Device (Type 17) - Length 27 - Handle 001bh]
  Physical Memory Array Handle  001ah
  Memory Error Info Handle      [Not Provided]
  Total Width                   2304 bits
  Data Width                    2252 bits
  Size                          2048MB
  Form Factor                   09h - DIMM
  Device Set                    [None]
  Device Locator                A0
  Bank Locator                  Bank0/1
  Memory Type                   02h - Unknown
  Type Detail                   0000h -
  Speed                         1333MHz
  Manufacturer                   
  Serial Number                  
  Asset Tag Number               
  Part Number                    
[Memory Device (Type 17) - Length 27 - Handle 001ch]
  Physical Memory Array Handle  001ah
  Memory Error Info Handle      [Not Provided]
  Total Width                   256 bits
  Data Width                    196 bits
  Size                          2048MB
  Form Factor                   09h - DIMM
  Device Set                    [None]
  Device Locator                A1
  Bank Locator                  Bank2/3
  Memory Type                   02h - Unknown
  Type Detail                   0000h -
  Speed                         1333MHz
  Manufacturer                   
  Serial Number                  
  Asset Tag Number               
  Part Number                    
[Memory Device (Type 17) - Length 27 - Handle 001dh]
  Physical Memory Array Handle  001ah
  Memory Error Info Handle      [Not Provided]
  Total Width                   2304 bits
  Data Width                    2252 bits
  Size                          2048MB
  Form Factor                   09h - DIMM
  Device Set                    [None]
  Device Locator                A2
  Bank Locator                  Bank4/5
  Memory Type                   02h - Unknown
  Type Detail                   0000h -
  Speed                         1333MHz
  Manufacturer                   
  Serial Number                  
  Asset Tag Number               
  Part Number                    
[Memory Device (Type 17) - Length 27 - Handle 001eh]
  Physical Memory Array Handle  001ah
  Memory Error Info Handle      [Not Provided]
  Total Width                   256 bits
  Data Width                    196 bits
  Size                          2048MB
  Form Factor                   09h - DIMM
  Device Set                    [None]
  Device Locator                A3
  Bank Locator                  Bank6/7
  Memory Type                   02h - Unknown
  Type Detail                   0000h -
  Speed                         1333MHz
  Manufacturer                   
  Serial Number                  
  Asset Tag Number               
  Part Number                    
[Memory Array Mapped Address (Type 19) - Length 15 - Handle 001fh]
  Starting Address              00000000h
  Ending Address                007fffffh
  Memory Array Handle           001ah
  Partition Width               01
[Memory Device Mapped Address (Type 20) - Length 19 - Handle 0020h]
  Starting Address              00000000h
  Ending Address                001fffffh
  Memory Device Handle          001bh
  Mem Array Mapped Adr Handle   001fh
  Partition Row Position        01
  Interleave Position           [None]
  Interleave Data Depth         [None]
[Memory Device Mapped Address (Type 20) - Length 19 - Handle 0021h]
  Starting Address              00200000h
  Ending Address                003fffffh
  Memory Device Handle          001ch
  Mem Array Mapped Adr Handle   001fh
  Partition Row Position        01
  Interleave Position           [None]
  Interleave Data Depth         [None]
[Memory Device Mapped Address (Type 20) - Length 19 - Handle 0022h]
  Starting Address              00400000h
  Ending Address                005fffffh
  Memory Device Handle          001dh
  Mem Array Mapped Adr Handle   001fh
  Partition Row Position        01
  Interleave Position           [None]
  Interleave Data Depth         [None]
[Memory Device Mapped Address (Type 20) - Length 19 - Handle 0023h]
  Starting Address              00600000h
  Ending Address                007fffffh
  Memory Device Handle          001eh
  Mem Array Mapped Adr Handle   001fh
  Partition Row Position        01
  Interleave Position           [None]
  Interleave Data Depth         [None]

also you are running F3 bios from mid 2009 you may get better compatibility with a later bios but they are all quite dated now with the most recent F9 dated mid 2010 http://uk.gigabyte.com/products/prod...?pid=3164#bios although i wouldnt recommend flashing bios if you are not sure what you are doing as it may not even help and can have severe consequences when done wrong

On a side note as i dont think it is causing your problem you have a large amount of very old drivers on your system that pre date windows 7 you might want to look into updating these at some point although it might be safer to sort your problem first before introducing more variables

Code:

iirsp.sys 13/12/2005 21:47:54 
nfrd960.sys 06/06/2006 21:11:48 
hardlock.sys 30/11/2006 17:12:07 
whfltr2k.sys 26/01/2007 08:04:37 
adpu320.sys 28/02/2007 00:04:15 
adpahci.sys 01/05/2007 17:30:09 
arc.sys 24/05/2007 21:27:55 
GEARAspiWDM.sys 01/02/2008 14:06:03 
SiSRaid2.sys 24/09/2008 18:28:20 
sisraid4.sys 01/10/2008 21:56:04 
adp94xx.sys 05/12/2008 23:54:42 
lsi_fc.sys 09/12/2008 22:46:09 
aksfridge.sys 08/01/2009 07:59:54 
arcsas.sys 14/01/2009 19:27:37 
ql2300.sys 22/01/2009 23:05:06 
vsmraid.sys 31/01/2009 01:18:57 
elxstor.sys 03/02/2009 22:52:11 
stexstor.sys 17/02/2009 23:03:36 
amdsbs.sys 20/03/2009 18:36:03 
lsi_scsi.sys 16/04/2009 22:13:50 
spldr.sys 11/05/2009 16:56:27 
lsi_sas.sys 19/05/2009 00:20:23 
lsi_sas2.sys 19/05/2009 00:31:48 
megasas.sys 19/05/2009 01:09:46 
ql40xx.sys 19/05/2009 01:18:11 
MegaSR.sys 19/05/2009 01:25:54

No problems see how you get on and let us know :)