BSOD (almost!) always onStartup (ntoskrnl.exe IRQL_NOT_LESS_OR_EQUAL)

Hello.
I have BSOD almost constantly appearing during system startup (after reset ONLY and very rarely on random occasions, it doesn't happen when PC comes back from hibernation / sleep mode).
I'm saying almost constantly because sometimes it BSOD's 20 times in a row and eventually after multiple resets it stops and I can use my PC for next couple days (up until next system reset).
There is no particular time in startup when it happens, sometimes after or before windows loading screen, sometimes couple seconds after desktop has been loaded.

Mostly it is IRQL_NOT_LESS_OR_EQUAL) error, but couple times I had another one: PAGE_FAULT_IN_NONPAGED_AREA and SYSTEM_SERVICE_EXCEPTION at netio.sys.
SF Diagnostic attached.

Any help apreciated, PC is my main work tool and this particular one is quite essential for my company

Thanks in advance!

Code:

BugCheck A, {6800036e560, 2, 1, fffff800032e571f}

Probably caused by : memory_corruption ( nt!MiReplenishPageSlist+100 )

Code:

.trap 0xfffff88003ab36c0
NOTE: The trap frame does not contain all registers.
Some register values may be zeroed or incorrect.
rax=00000040000124c7 rbx=0000000000000000 rcx=fdffffffffffffff
rdx=000000000000004f rsi=0000000000000000 rdi=0000000000000000
rip=fffff800032e571f rsp=fffff88003ab3850 rbp=fffffa8003a80118
 r8=fffff800034fa440  r9=fffffa8003a80000 r10=fffffa8003a80138
r11=fffff88003ab38a8 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=0000000000000000
iopl=0         nv up ei pl nz na po nc
nt!MiReplenishPageSlist+0x100:
fffff800`032e571f f00fba6b1000    lock bts dword ptr [rbx+10h],0 ds:00000000`00000010=????????

The lock bts instruction is used to perform a atomic Bit Test and Set operation, which stops any hardware interrupts, interrupting the processor and reading or writing to the same location.

I believe nt!MiReplenishPageSlist is used to update a singly linked list, this since it's a Memory Manager Internal function, and therefore won't be documented. My assumption is based upon two facts, there's a data structure called by Windows to represent the list header of a singly linked list called _SLIST_HEADER, and because of the Assembly instruction called lock bts.

Code:

0: kd> dt nt!_SLIST_HEADER
   +0x000 Alignment        : Uint8B
   +0x008 Region           : Uint8B
   +0x000 Header8          : <unnamed-tag>
   +0x000 Header16         : <unnamed-tag>
   +0x000 HeaderX64        : <unnamed-tag>

Code:

0: kd> knL
 # Child-SP          RetAddr           Call Site
00 fffff880`03ab3578 fffff800`032bfde9 nt!KeBugCheckEx
01 fffff880`03ab3580 fffff800`032bea60 nt!KiBugCheckDispatch+0x69
02 fffff880`03ab36c0 fffff800`032e571f nt!KiPageFault+0x260
03 fffff880`03ab3850 fffff800`032e5c4f nt!MiReplenishPageSlist+0x100
04 fffff880`03ab38b0 fffff800`032de1f7 nt!MiRemoveAnyPage+0x24f
05 fffff880`03ab39d0 fffff800`032daa26 nt!MiResolveDemandZeroFault+0x577
06 fffff880`03ab3ac0 fffff800`032be96e nt!MmAccessFault+0x5c6
07 fffff880`03ab3c20 00000000`7346e33d nt!KiPageFault+0x16e
08 00000000`07498104 00000000`00000000 0x7346e33d

Code:

0: kd> !irql
Debugger saved IRQL for processor 0x0 -- 2 (DISPATCH_LEVEL)

Run Driver Verifier to scan for any corrupted drivers which may be causing problems, this program works by running various stress tests on drivers, in order to produce a BSOD which will locate the driver; run for least 24 hours:

• Driver Verifier - Enable and Disable

   Information

Additional Help - Using Driver Verifier to identify issues with Drivers

No Service Pack 1?

Code:

2: kd> vertarget
Windows 7 Kernel Version 7600 MP (4 procs) Free x64
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 7600.17273.amd64fre.win7_gdr.130318-1532
Machine Name:
Kernel base = 0xfffff800`03219000 PsLoadedModuleList = 0xfffff800`03455e70
Debug session time: Wed Dec  4 11:11:25.113 2013 (UTC + 0:00)
System Uptime: 0 days 0:01:06.768

• Learn how to install Windows 7 Service Pack 1 (SP1)

Service Pack 1 has provided many security and stability updates for Windows 7, which would be highly beneficial for your system.

I noticed in the last bugcheck, that avast! was the last running process, this is not say avast! is necessarily the problem, but from past experiences it can cause problems so please remove with the avast! Removal Tool for at least troubleshooting purposes.

Install and perform full scans with:

• Malwarebytes : Free anti-malware download
• Microsoft Security Essentials | Protect against viruses, spyware, and other malware

   Information

Remember to install the free version of Malwarebytes not the free trail; untick the free trial box during installation. MSE is the most lightweight and compatible with the Windows 7 operating system

You can also view this thread for a complete free and lightweight security protection combination:

• Good and Free system security combination.