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Windows 7: BSOD on system boot, cant reach login. cng.sys

17 Sep 2015   #1
wildozer

Windows 7 Home Premium 64bit
 
 
BSOD on system boot, cant reach login. cng.sys

Hi there,

So the other day I booted my computer up like normal and it got halfway through the four windows lights coming together to create the windows logo (after bios boot and just before user login screen) when it flashed with a quick blue screen then rebooted on its own accord. There's no way I can get past this point in the system boot that I've been able to figure out and I was hoping that someone here could help me.

I turned off automatic restart on system failure and it said something about the file cng.sys, so I am thinking that file has become corrupted somehow. Or am I way off. I don't recall installing anything new hardware or software-wise recently and I'm unsure how this happened.

Things I have tried:
Automatic startup repair
Removing CMOS battery and reinserting
Removing individual RAM sticks and trying each of the two separately
Unplugging everything from the back except the mouse and keyboard
Boot to safe mode
Flashing a BIOS Update
Inserting Windows 7 CD and doing a system restore and the other repair options on there
SFC scan with the Windows CD

I assembled the computer myself in 2010 sometime and it has
Gigabyte h67ma-ud2h-b3 motherboard
2x2GB RAM
GTX 560
Intel i5 2500
Corsair PSU - 500 watt I think?
card reader
optical drive

It seems I'm able to access the command prompt. Is there a way I can replace the cng.sys file with a good one or is that not something that would work? I am trying to avoid reinstalling windows as there is data that I would like to keep on the drive.

Any help is appreciated.
Thanks.




My System SpecsSystem Spec
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19 Sep 2015   #2
wildozer

Windows 7 Home Premium 64bit
 
 

I have since run a chkdsk, but still crashingbat the same point.
Can anyone help me please? I'm at a loss here
My System SpecsSystem Spec
19 Sep 2015   #3
Pauly

Win7 Ultimate X64
 
 

cng.sys is a native windows file if there was a problem with sfc scan should repair it.
What were the results of your sfc scan ?

Have you checked your bios settings ? if you remove the cmos battery all settings will return to default so check everything is correct, there are some settings that if changed would leave your system unbootable for example changing sata mode from IDE to AHCI or vice versa and ram settings if they were manual before ie voltages/frequency
My System SpecsSystem Spec
.

19 Sep 2015   #4
wildozer

Windows 7 Home Premium 64bit
 
 

Hi Pauly. So I just ran another SFC and this is a picture of the results.
Imgur: The most awesome images on the Internet
Still no startup

I don't know what BIOS settings to change, everything seems pretty much normal and in order. I never changed any voltages to begin with. I'll have another look.

How can I go about accessing that log file from command prompt?

At this stage it looks like I might need a new hard drive, reinstall windows and then recover my files off my current drive. But I'd rather not take that option if possible. Is my drive maybe failing?
My System SpecsSystem Spec
19 Sep 2015   #5
Pauly

Win7 Ultimate X64
 
 

If you navigate to your system drive you will find the log at %root%/windows/logs/cbs/cbs.log which you can then copy to a flash drive from the command prompt. If you can upload that file we can get one of our SFC gurus to hopefully help you out. This may or may not be related to your boot issues.

While you are there navigate to the windows/minidump folder and see if you have any dump files for us to analyse this would help greatly in narrowing down your issue
My System SpecsSystem Spec
20 Sep 2015   #6
wildozer

Windows 7 Home Premium 64bit
 
 

So I tried to copy to a USB in the command prompt but got an access denied error message.

I used this command here:
findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"e:\sfcdetails.txt"

I just guessed e drive, but tried f and g also, but they gave a wrong file path error.

I altered from: findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"%userprofile%\Desktop\sfcdetails.txt"

Since I obviously can't access the desktop.

I found the original command on this page. SFC /SCANNOW Command - System File Checker

So basically I'm not sure how to access the log file since I can't access the desktop.
My System SpecsSystem Spec
20 Sep 2015   #7
NoelDP

Microsoft Community Contributor Award Recipient

Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
 
 

Please just post the CBS.log file (compressed)

You shouldn't have a problem copying the CBS.log file - use the following command

COPY C:\Windows\logs\cbs\cbs.log %userprofile%\desktop\cbs.log

That will put it on the desktop (OK - you can't see it at the moment!)

Now hunt for your USB stick - make sure that it contains a recognisable file in the root folder before you insert it on the machine (a Notepad file named TEST.TXT would be good)

run the following commands

DIR D:\TEST.TXT
DIR E:\TEST.TXT
DIR F:\TEST.TXT
DIR G:\TEST.TXT

Which one works?
Substitute the functional drive letter into the following command (for <drive>)

COPY %userprofile%\desktop\cbs.log <drive>:\CBS.LOG

It would be a good idea to also copy the Persist files, so use this command as well

COPY C:\Windows\Logs\CBS\CBSPersist*.* <drive>:\

Then you can close the machine down, and move the stick back to your functional machine and compress the copies for upload.
My System SpecsSystem Spec
20 Sep 2015   #8
wildozer

Windows 7 Home Premium 64bit
 
 

Hi Noel.

So i finally got the log files with your guidance, thank you. Turns out i needed to be using D:\Windows... instead of C.

I've attached the compressed CBS.log but i'm going to have to give an external link to the persist files since as once all compressed, it added up to ~70mb. I have no idea if that's normal or not.

Persist files are here:
Mega File Upload - Log Files.rar

Will.
My System SpecsSystem Spec
21 Sep 2015   #9
Pauly

Win7 Ultimate X64
 
 

That's great a good step forwards, we will have to wait and see what Noel says about the SFC results as I really don't know what I'm looking at but in the mean time did you try recovering the dump files from your machine ? would be good to have as look at these and may give us a better idea of whats causing the crash if its anything other than windows file corruption
My System SpecsSystem Spec
26 Sep 2015   #10
NoelDP

Microsoft Community Contributor Award Recipient

Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
 
 

Unfortunately the file doesn't contain any useful data
Please upload the C:\Windows\Logs\CBS\CbsPersist_20150821095015.cab file - you'll have to zip/rar it, since the forum doesn't accept bare cab files.
My System SpecsSystem Spec
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 BSOD on system boot, cant reach login. cng.sys




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