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Windows 7: Harry Potter and the 0x7A, vanishing hard drives and poor timing woes

02 Feb 2011   #1

Windows 7 Ultimate 64-bit
Harry Potter and the 0x7A, vanishing hard drives and poor timing woes

Right... where to start... The beginning I guess.

A couple of weeks ago, I came back from work to find a BSOD staring back at me. My computer's permanently on, you see. It wasn't the first BSOD I've seen on my computer but the first in a very long time and the previous ones were easy to diagnose. Faulty drivers.

This one, however, is proving to be harder for me to diagnose. As I understand it, the 0x7A error is related to problems accessing the paging file, so naturally, I checked the state of the drive. There were errors present so I went through the motions of repairing it with chkdsk with the /f and /r flags set. That seemed to do the trick. It soon crashed again, however. It was a persistent back and forth between me and the computer for the rest of the week until the weekend when the computer really went on the offensive. For the Friday and Saturday, it was crashing on me constantly. Would not stay stable at all. On the Sunday, however, It decided to stay stable for about 2 days. I hadn't really done much to it other than a system file repair which seemed to make it work.

I should probably mention that every time it had crashed before, it had either crashed while I was away from the machine, or it was crashing during boot with 0x50 BSODs while I was trying to fix it. The next time it crashed though, I was sat at the machine and I had the task manager and performance monitor page open on the Disk tab and I noticed something. All the hard drives had vanished. All the graphs had a stable output, like a flatline. Programs I had running were still accessible, but gradually they started entering the not responding state until finally the mouse locked up too. The computer stayed this way for about a minute or two before producing the 0x7A BSOD. I continued to monitor the task manager and performance monitor every time the computer crashed to try and find out what was causing the crashes but it was pretty inconclusive. On rare occasions all the drives would vanish. Maybe once or twice it happened. On other occasions they remained listed but the symptoms were the same. In fact the symptoms are the only constant of the entire fault.

I've had a few different BSODs from playing about with the machine to try and repair it. Aside from the 0x7A, I've seen 0xF4 a few times too. It's important to note that everytime these BSODs occur, the Hard Disks enter a state where they are unable to read or write so I cannot provide any minidumps because there simply aren't any.

As far as I could tell, These errors seemed consistent with a controller failure to me, but I queried that several times as I wouldn't have thought I would lose the IDE drives (Hard Disk and DVD drive) on that one occasion. I have also suspected the Power Supply, the system Hard Disk and RAM.

I tested the health of the Hard Disk and the Disk is indeed unhealthy. I tested all the disks several times just in case there were inconsistencies created by a faulting controller, but the result was the same every time. The system disk is dying, so I've ordered that as a replacement. That's fine. The doubts I had before about what is fundamentally causing the problems started to go for a while once I had realised how unhealthy that drive was. As far as I was concerned, the mystery was solved. Then, shortly before bed time last night, my other, much healthier SATA drive vanished. Checked Disk Management and it wasn't there either. Rebooted and entered the BIOS and then BOTH SATA drives were gone.

The head scratching begins again.

This diagnosis has been so problematic. There's so many potential faulting components involved. The only component I know for sure is dying is that Hard Drive, but I think that I have just been lucky to discover its unhealthy state in trying to diagnose another problem.

The main cause for the concern and frustration is that whatever this problem is, the timing is awful. Socket 775 architecture's on its way out and components are becoming a little rarer. I would love to just build an i3/i5 system instead, but I would need to get a new CPU, new Motherboard and new RAM, of course, to make the move and I can't really afford to buy many components as it is right now. In fact, the luck I've had so far diagnosing all this, I would end up building an i3/i5 system only to find out that the PSU is at fault in the first place, so I will have two systems I can't use.

So, to limit my costs as much as possible, can anybody think of anything I've perhaps overlooked? I would test the rails on the PSU but because the fault is so sporadic, I could end up staring at the display of the multimeter for a whole day and still not get a conclusive reading. I don't have access to other parts to test everything either.

Any help would be appreciated.

TL;DR version: BSODs, vanishing hard drives, can't afford to buy entire new system, need to diagnose what is failing, already tested RAM and Hard drive health, discovered one failing hard drive, healthy hard drive still vanishing for some reason.

My System SpecsSystem Spec
28 Feb 2011   #2

Win 7 64-bit

Did you ever figure out the cause of the problem or get your computer to work? I registered here to respond to this since I have had the EXACT same problem for a few months now. What I've done so far:

tried 3 different hard drives
tried 3 different power supplies
replaced RAM for no reason as it passed Memtest86+
tried 3 different sets of SATA cables
replaced the motherboard
tried both IDE and AHCI mode for SATA drives

And I still do not have a properly functioning computer. It is about to drive me crazy because it does not make any sense. All my temps are ok and the problem occurs whether case is on or not. I thought maybe CPU but I have run the Prime95 tests for several hours with no problems - and I am not sure how a CPU problem would be causing the drives to disappear without ever showing other symptoms. The same problem also occurs on my Linux install which means it is hardware related and not just a driver issue.

So I am left wondering if it is something wierd - such as EMI/RF interference (from what I don't know) or bad power coming out of the outlet (however all voltages check within 1-2% of nominal coming out of the power supply, well within the ATX spec). Anyone have ideas?
My System SpecsSystem Spec

 Harry Potter and the 0x7A, vanishing hard drives and poor timing woes

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