Once in a while I'd be browsing the web, on MS Word or have left my PC on for an overnight download, and I'd get a totally unexpected BSOD. 4 months and 24 BSODs later I'm still perplexed as to what's wrong.

Hitting up BlueScreenView it looks like,

  • Most common error: IRQL_NOT_LESS_OR_EQUAL (18 times)
  • Followed by KERNEL_MODE_EXCEPTION_NOT_HANDLED (only 4 times)
  • IRQL error is mostly caused by
    • atikmdag.sys - ATI Radeon Kernel Mode Driver (6 times)
    • ndis.sys - NDIS 6.20 driver (3 times)
    • usbport.sys - USB 1.1 & 2.0 Port Driver (3 times)
    • Rt86win7.sys - Realtek 8101E/8168/8169 NDIS 6.20 32-bit Driver (3 times)

Reading up on google results for BSODs on each sys files lead me to think it's a problem with either:

  • corrupt drivers
  • corrupt memory
  • fried USB ports
  • failing hard drive
  • dying graphics card
  • dying power supply
  • dying mother board

I ran memtest for over 24 hours with no errors, and I've reinstalled virtually all the drivers I could think of. In regards to my graphics card driver BSODs occur with the latest driver and accompanying software as well as the version prior to it. Windows Updates are all up to date including the 'BlueScreen fixes'.

Here's a shot of all BSODs via BlueScreenView since July: alt text

Could someone, seeing the combination of sys files in question, simply direct me towards what could be causing this. I can't afford to rebuild a new system nor try replacing/unplugging single components and just wait for that 'time of the month' to see if it were the cause.

My setup

  • Windows 7 32-bit (installed in June)
  • ATI Radeon HD 4850
  • 2 GB Kingston stick
  • Intel Core 2 Duo E7500
  • MSI G31M3-L V2 Motherboard
  • Avast! Antivirus

I have not reformatted the machine and would like choose to do so only as a last resort (given the amount of time it would take for backing up and setting up software and settings again).

Update: (7 Nov)

I replaced the memory and after a day of use, within minutes ran into a whole set of new BSODs MEMORY_MANAGEMENT, BAD_POOL_CALLER and on 3rd restart Aero refused to turn on. Pulled out the the graphics card and went into Safe Mode but ran into yet again another BSOD (the original IRQL_NOT_LESS_OR_EQUAL).

I fired up a Fedora 11 Live CD to ready a reformat. And while backing up data, Fedora suddenly froze up. It was without a doubt a hardware issue, a reformat would just not have fixed it.

I have now transported everything, except CPU (couldn't find thermal paste), to a friend's spare motherboard and installed a fresh 32bit Windows 7. If I don't get a BSOD within a month, it was the motherboard.


Random blue screen errors that involve random system files or drivers is usually a sign of defective memory.

I would run a memory tester http://www.memtest.org/

Download the prebuilt ISO, burn it to CD as an Image (not data), boot from that CD and run the memory test for a couple of hours or overnight to stress test the memory. It could take more than 24hours of stress testing before you get errors.

If you get errors, the next step is to test the memory modules one at a time (if you have more than 1 installed), to isolate the defective module.

Sometimes re-seating the memory modules will cure this issue.

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  • In my question I've mentioned that I have already done this. Twice in fact, and it ran for over a day. There were no errors. Is there any other tool I could perhaps use? – Jay Wick Nov 4 '10 at 22:32
  • FACT: You did not mention in you original post how long memtest ran, get your facts straight. You can edit your original post to reflect this new information. – Moab Nov 5 '10 at 3:11
  • I ran memtest for over 24, and at some point it looked like it had restarted. But should I have run it for longer though? (PS: 'facts straight'? lol sorry?) – Jay Wick Nov 5 '10 at 3:53
  • How often do the bsods happen? Usually 24 hours is enough, but I have seen cases where it took days. – Moab Nov 6 '10 at 22:19
  • On average 4 times a month. But following your idea that it could be memory, I completely replaced mine. The issue unfortunately got worse somehow (see update). But it pointed me in right direction, thanks again :) – Jay Wick Nov 7 '10 at 14:15

I would like to start out by stating the fact that BSODs are tricky to fix. What I would do is test out all hardware parts first (since changing out the registry would require a new OS).

The easiest thing would be to swap out the memory. (if you have memory to swap it with or to pull out one stick if there are two)

To do a hard drive test I would run a chkdsk /f (if you need help with this let me know).

To test the video card. I would take the video card out and see if the machine still has the issue without the video card.

If you have another power supply, I would change that out to rule out the power supply.

If there is still no avail at this point. I would reinstall the OS. (I know it's painful)

If this doesn't work, I would rebuild the system by buying a new motherboard and processor that is compatible with the rest of the system.

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  • I've run chkdsk and wddiag, so it might not be the HD. I'll try replacing parts individually if I don't get any software testable answers. Thanks! – Jay Wick Nov 4 '10 at 22:36

I had the same problem and I found out 14 faulty capacitors (https://i.stack.imgur.com/2Rnrs.jpg) Some of the capacitors are under the processor (https://i.stack.imgur.com/Bv2dw.jpg) All of them were bulged, MSI fixed the problem adding SOLID CAPS on their next motherboard model

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  • why is this down voted? perhaps someone has a similar situation in future – Jay Wick Jul 3 '17 at 0:08

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