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Ever since we had some crazy power surges last week my 64 bit Windows 7 PC has been acting strange. My USB network adapter disconnects from the wireless and can't detect the signal. I have to disable/reenable the adapter to detect it again. Also my wife has reported that the PC has rebooted a few times while I'm not sitting at it.

Today, I finally caught the reboot while I was using the PC. I got this blue screen of death. Stop Code 0x00000109:

"Modification of system code or a critical data structure was detected."

I followed the advice at the linked article and ran a memory test. I used memtest86 and it has already found around 300,000 errors out of 8 gigs of ram.

Now I'm worried -- what are the odds this is isolated to just my memory and not a system wide problem? Isn't there a good chance that many other components are fried? More importantly, how can I test those other components? Are there tools similar to memtest I can use to test my motherboard/video card/power supply? If these are vender specific, is it typical for vendors to provide testing tools?

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Every time I've ever dealt with a system that's seen a significant surge, the entire thing ends up needing to be replaced. When I was younger and working in a PC shop, a customer's system took a surge and all the parts slowly failed over the course of the next several months. First the RAM, later a CPU, then MB, etc. – afrazier Feb 4 '11 at 15:59
One other thing to mention: Software for testing your hardware can only definitively verify that it's bad -- none can verify that your hardware is good. It doesn't matter if all your tests come back OK if your system still throws a BSOD every 5 minutes after a clean install of Windows. – afrazier Feb 4 '11 at 16:02

First off I suggest that you invest in a high quality surge protector and make sure that your PC is protected. Another suggestion is investing in a UPS (Uniterupted Power Supply) as these will supply power to your computer during power outtages, and depending on the type will notify your PC that power has been cut and will properly shut down your PC.

Also, with the fact that there are errors I want to make sure that you do replace those memory modules as (one) maybe more are bad.

Finally, before I get into actual testing, a fresh install of Windows may be a smart thing to do. If system files were being accessed at the time of the power outage, then they may have become corrupted.

With those things said, here are some tools that you can use:

  • Memory: Memtest86+ is the best option I have seen so far

  • Hard Drives: Ultimate Boot CD has a great collection of diagnositc software for testing all sorts of brands of HDD's

  • GPU: This is a little more difficult as there is no (that I know of) targeted diagnostic software to test GPU's, however the use of benchmark software like FurMark can be used. Run the benchmark and if there are errors or system crashes then there is a possible issue

  • Power Supply: The best way to test these is to purchase a specific Power Supply tester which will measure the voltages output by the PSU and tell you if there are problems

  • CPU: Similar to the GPU there is no direct software to test that I know of. However you can use benchmark software like Prime95

  • Motherboard: This is very, very difficult to directly test. In my experience it's been if you know everything else is working, and there are still crashes. There are some symptoms that you may look at but there is no direct testing that can be done (besides replacing and checking).

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what about the motherboard? – Doug T. Feb 4 '11 at 15:28
@DougT. updated answer. :) – KronoS Feb 4 '11 at 15:31
sounds like the best option may be replacing the memory and then praying :) – Doug T. Feb 4 '11 at 15:41
That's where I would start. – KronoS Feb 4 '11 at 15:46
I would recommend buying a UPS over a surge protector. If your hardware is even remotely valuable, the extra cash is well worth it, and you have the added bonus of being able to work long enough to save files and shut down properly if the power goes out! – Shinrai Feb 4 '11 at 16:21

My experiences with power surges have never been good. I had one machine where nearly every component was toasted, whatever machine I put any part of it into started to get issues. After nearly 6 months i threw the entire thing out. UPS and surge plugs are alot higher up my shopping list now.

That said, you should be ok on the harddrives, and you can check them with s.m.a.r.t easy enough. The ram is toasted by the sounds of your memtest output, the real question is did the motherboard survive ? I'd suggest it's unlikely or at least unlikely in terms of being rock solid now, in which case you might be looking at a do-over more or less from scratch.

The psu may well be affected also, I had this happen recently to a machine from a power surge.

Smart test your drives, stress test the cpu (using something for windows, else "stress" for linux), and get new ram if you think its worth the gamble.

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A clean install might be your best bet in this case. If there are any hardware issues, they may pop up during the install.

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First step, replace the power supply. Surge suppressors can only stop so much, it's better to have invested in a UPS as they have a stiffer power conditioning system that is better at stopping over-voltage and spikes than a couple MOVs arranged accross the various circuits in the hopes they dissipate all the power crazieness.

Unless the power surge got in by other means like a modem (thankfully no longer a secondary lighting strike path for a lot of people), usually the power supply absorbs the excess energy as the voltage regulators do their job.

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