Windows 7: [SOLVED] random BSOD around "ntoskrnl.exe+7cc40"

hello forum,

i just wanted to share the findings regarding my BSOD error symptoms.

to get assistance with troubleshooting you should follow the instructions given in: http://www.sevenforums.com/crashes-d...tructions.html

however, as very basic initial steps i personally prefer this approach:

• create a bootable CD for memtest86+ from Memtest86+ - Advanced Memory Diagnostic Tool and let it run for 24 hours. if there is just one single error it means your memory is definitely bad. if there are no errors your memory is "most likely" OK.
• get a copy of BlueScreenView from NirSoft - freeware utilities: password recovery, system utilities, desktop utilities to easily read the crash dumps.

on my system i was getting sporadic BSOD crashes - each time random stop codes including:

• DRIVER_IRQL_NOT_LESS_OR_EQUAL
• IRQL_NOT_LESS_OR_EQUAL
• KMODE_EXCEPTION_NOT_HANDLED
• MEMORY_MANAGEMENT
• PAGE_FAULT_IN_NONPAGED_AREA
• PFN_LIST_CORRUPT
• POOL_CORRUPTION_IN_FILE_AREA
• SYSTEM_SERVICE_EXCEPTION
• SYSTEM_THREAD_EXCEPTION_NOT_HANDLED

i wasn't able to make out any pattern. the only thing in common was the crash address that would always be "ntoskrnl.exe+7cc40".
in many cases the crash dumps will indicate a particular driv€r to be causing the trouble. but with my system this was not the case.


by coincidence i had identified a pattern how to reproduce a BSOD (by doing certain actions in a pre-defined sequence). so this would allow me to proceed with systematic troubleshooting.


in the end it turned out i was using some defective RAM - or "strange" RAM, at least.
it took me quite a while, because of the following reasons:

• BSOD seemed to occur randomly / sporadically
• BSOD was showing random stop codes
• memtest86+ did not show any erros!

conclusion:
i would recommend the following approach:

• use memtest86+ to check if there are any "obvious" errors with your RAM
• use BlueScreenView to check if any device driv€r seems to be causing the error
• in case you're getting "random" errors like me (as outlined above): take one more closer look at your RAM

in case this still doesn't get you any further: follow the posting instructions to attach the required files. the guys on this forum are doing a great job and will most likely be able to point you in the right direction for additional troubleshooting.

cheers, francoiste

my memory was showing these strange symptoms due to physical damage.
please see the <attached picture>.

if you look at the photograph it appears just so obvious.
but believe me, you won't detect it with your bare eyes.
you need either a magnifying glass or (as in my case) a high-end photographic camera with super zoom.

note: i'm not sure if this damage was there right from the beginning (DOA) or caused by my excessive testing (adding, removing, swapping the memory modules endless times).

anyhow,
so what's the message?

first: be very careful when inserting your memory modules into the slots.
some brands / modules don't have a very robust design, obviously.

second: the scary part is that neither memtest nor windows detected any errors when doing a memory validation.
the only visible symptoms: the physical damage led to sporadic errors (blue screens) during regular operation.
so it's still very difficult to tell whether a memory module is 100% OK or just 99% OK ...


cheers, francoiste

you know francoiste I have been having the same blue screens that you had and once in a while the screen freezes with a few lines on it. Now i havent had a blue screen in a few hours, but earlier today I had like 5 and always kmode exception, driver irql, etc... you know what they are because you had them too, and my memory is also checking out ok on memtest. Maybe i should just buy new memory stick but i cant open my computer because i have 39 days left on my warranty from hp and they said if i open it they will not fix it for free... so that is why i cant check out my ram sticks but from what you wrote I really think that i may have a similar problem, the ram came in the computer and they are only 8-9 months old, but i wonder if some dirt or heat in there caused something to happen or maybe one of the sticks is loose or the contacts are dirty. I will let you know what happens!
its weird that now im going for over 4 hours and earlier today i had 5 blue screens in a row then i did a system restore, plus i REINStalled windows 7 yesterday from the 3 dvds that hp sent me and was doing good until today, cpu on all night without a problem then today i got one and 5 more then i do system restore and now ok, so maybe its not my ram it may be an update that was downloaded after I system restored to but if i get another blue screen I will check my ram physically if HP lets me open it up thanks man
James

I guess I may as well have the same issue because everything works fine but whenever I play games, I get BSOD.

yeah i thought i fixed this problem until today when i get another ntoskrnl error with system service exception, I just checked out my RAM and it looks fine physically now i will run memtest again but i am going to have to send this laptop back to HP, because its almost definitely hardward related and i only have 30 days left on warranty,

Thanks Francoiste,

I have had the same issue about 10 times with "ntoskrnl.exe+7cc40" being the culprit every time. I checked my systems and noticed that the mobo was only recognizing 4 GB of RAM (I have three sticks of 2GB installed), and sure enough after testing each stick I found one that was faulty. Like you said before, the memtest86+ does not detect this.

in post #2 i had attached some photos that nicely show the physical damage of the memory modules.
it took me quite some time to generate those photos.

i just noticed they are gone! who deleted my attachments? and why?

It was probably done to clean up space on the server. I believe as threads get older, the attachments are automatically cleaned up or the administrators manually clean them up. I suspect the former.

well, i do understand that it makes sense to regulary purge chrash dump files uploaded for the purpose of individual troubleshooting.

however, i'm convinced that my pictures of the memory modules will remain "interesting" for a couple of years, at least.

actually, i'm not really willing to contribute anything further as long as either some moderators will edit my posts (has happened in the past) or whatever kind of mechanism is deleting my file attachments (as discussed here).
that's an absolute show-stopper.

anyhow, for now i'm adding the pictures once more. <please see file attachment>

I have informed an administrator about the missing attachments.