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Okay, I'm a bit knowledgeable with pooters and such, but i'm confused. My computer is dying slowly, and I'm not sure what part is causing this.

Computer details: Vista, dell machine, intel Q6600, 2.4 Core Duo (quad core), standard memory and drive (unknown manufacturer).

Symptoms: I would best describe the symptoms as memory corruption. After a couple days on, I start getting applications crashing or failing to open for a lack of "resources". Sounds are corrupted. Onscreen text gets corrupted; the characters of text are garbled, not the pixels on the screen. Video memory seems untouched as I haven't seen any misplaced pixels.

Recently I've lost files on disk. I've also experienced errors reporting a supposed lack of disk space, even though I have fifty gigs free.

There was one point where I couldn't get to the POST when booting up. After I cleaned everything (see next) this hasn't happened.

Diagnostic steps: First thing I did was clean the case. There was a lot of dust buildup on heatsinks, so I cleaned all that up. No help. Next, I disconnected and reconnected everything, from power cables to memory (did not reseat cpu). No change. Last, I ran the standard vista memory diagnostics and ran checkdisk. Both reported no errors found. I have not run any POST tests, now that I think about it.

I'm at a loss at this point. Disk appears fine, memory too. I'd expect motherboard issues to result in the thing not booting up, yet it does every time.

What should I be looking at? What more can I do?

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is the machine overclocked? –  NoCarrier Jul 31 '09 at 23:19
    
Have you formatted the drive? To be frank it sounds like a virus more than anything. Run chkdsk on all partitions possible and if the problem persists, recovery –  Ciaran Aug 1 '09 at 0:15
    
I agree with everyone saying it's most likely a virus. Have you tried running an antivirus program? –  Sasha Chedygov Aug 1 '09 at 2:30
    
not overclocked; I RANU and don't install apps I don't fully trust. I also run chrome. No AV, but I do let defender run. –  Will Aug 1 '09 at 16:54
    
I've ordered a new system drive (10k rpm) and am going to do a fresh install of 7. Managed to limp along until now. –  Will Aug 13 '09 at 11:52
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7 Answers

up vote 8 down vote accepted

It seems like software problems have not at all been ruled out. Viruses, spyware, and just the unfortunate but inevitable cruft that builds up on a machine running basically any operating system over time tend to cause all sorts of problems, including all of the ones you have described. Wiping out your entire OS is a bit of a drastic step, so I would recommend grabbing a LiveCD for some big linux distro like Kubuntu or SuSE and seeing if it works without any sort of errors. Linux will generally give you pretty descriptive error messages (try typing dmesg on a console) for any hardware problems, so if it turns out your hardware is failing, you might get some additional clues too.

Also, like NoCarrier asked, if you have been doing any overclocking, you should definitely consider toning it down.

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+1 for possible virus, does not sound like hardware to me –  Ciaran Aug 1 '09 at 0:16
    
If I can find a livecd with a suite of test tools I'll try that. I don't relish the thought of running linux for a week to see if anything pops up. –  Will Aug 1 '09 at 16:56
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If you're positive that memory and disk are fine, (I don't recall if chkdsk alerts you of SMART errors on your HD), we can only narrow it down to

  • motherboard
  • CPU
  • power supply.

Your system boots consistently, so i think we can rule out the PSU. I would check to see if your CPU fan is operational and if your CPU heatsink is properly seated. Run a few monitoring apps to see how hot your CPU gets.

That said, you could have a defective motherboard or a defective CPU.

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+1 for checking fan and heat sink. I've had this problem before and it turned out my CPU was simply overheating. –  Sasha Chedygov Aug 1 '09 at 2:28
    
+1 Power supply is common to "everything" –  gbarry Aug 1 '09 at 6:36
    
Verified heat sink. Its very securely connected to the motherboard and the fan is screwed into it. That's why I didn't reseat the cpu; I didn't have the tools available to get it out without possibly damaging something. –  Will Aug 1 '09 at 16:57
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From experience I would recommend carefully gutting your machine and visually inspecting your cpu, ram, and video card very carefully. This comes from 1 (and just one) time where I identified a bad processor by a discoloration on the underside of it--the machine worked fine but would crash under heavy loads.

Realistically though it sounds like you're gearing up for some good ole "swap a component and see if it fixes it". It always sucks if you don't have a donor machine to borrow known-good parts from.

My gut feel is that you should start with the motherboard; you could consider ordering a new one and using it for a few days to see if it fixes the issue. If not then return it and move on to RAM or the processor--when you find the culprit you'll already have your replacement.

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If its hardware I do suspect its the motherboard. Switching it out for a new version of the same will probably be impossible; or rather hard enough so that replacing the whole machine would be preferrable. –  Will Aug 1 '09 at 16:59
    
It shouldn't be that difficult to track down a replacement on the cheap; just make sure you get one that supports the proc's pin-out and FSB speed, RAM frequencies, and cards you already have. Chances are that you can get a top-of-the-line board for el-cheapo--it's always a bonus of buying last-gen stuff :-D –  STW Aug 1 '09 at 20:23
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If it's a DELL machine, try the bundled diagnostics. They can test almost every possible failing part on a machine.

Every time I've had weird problems with DELLs, diagnostics have found the culprit (so far it has been dead memory, hard drive fan dying and motherboard failing.)

Do not go and buy a new part just because it may be the part failing. You'll probably regret it.

My gut feeling (based on the cleaning issue) is that the MB is the culprit, but this doesn't help you much now, does it?

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I'll look into the dell diags. Not sure if they're still available on the machine as I've wiped the original OS and installed a crapware free version. –  Will Aug 1 '09 at 16:58
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The hard drive is almost always the first to go. Try Chkdsk /f

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I didn't run it from the command line. It came back with no bad sectors or other errors, so /f wouldn't have made a difference. –  Will Aug 1 '09 at 17:01
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Although you might not like it, it sounds like you are going to have to format your harddrive (to erase everything) and re-install Vista all over again.

Because this is a destructive (you will lose all your files) route, make sure you have virus-free backups. Many security suites can scan removable devices.

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I'll be doing this when 7 is available over msdn, I guess. –  Will Aug 1 '09 at 17:01
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The best way to debug a system issue is to go step by step making one change at a time from a known good baseline. I can think of a few steps I would do. Be sure to back-up your important files before going further.

From the symptoms you describe, my first hypothesis is that the OS is corrupt or the system has a virus. You could boot to a Knoppix DVD an poke around. I definitely would do a clean install of the OS as step one, making sure to also install an up-to-date virus scan program and scanning your back-up made previously. Reinstalling the OS sounds drastic, but in the long run, it likely will save time if you're spending a lot of time debugging the issue without taking this measure.

If, after the clean install of the OS, you are still getting memory corruption type issues, only then, would I suspect hardware issues. The symptoms up to POST hang sound likely to be software related. The POST hang sounds more like a hardware or BIOS issue, but you'd have to duplicate it to solve that.

To isolate hardware issues, you want to strip down the motherboard to the bare essentials (CPU, Heatsink, 1 memory stick, 1 hard drive, keyboard, mouse, video), test and slowly add parts one at a time until you can reproduce the failure.

An other option is to test the subsystems using stress test programs (Memtest86, Prime95, some HD thrashing program) and work from there.

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Thanks for the suggestion. –  Will Aug 1 '09 at 17:02
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