System shut down suddenly, won't POST anymore. Please help!

Hello everyone,

I recently built a new computer and got it set up and working. I hadn't used it for a few days because I had yet to install a wireless card in it. I got my wireless card today and installed it, and then I booted up my computer and everything was fine. After about 5 minutes of usage, though, my computer just shut off.

Now when I try to turn my computer back on the following happens: all fans turn on EXCEPT my CPU fan. I get no POST noises. After a second or two my CPU fan will sort of "twitch" but it doesn't actually start spinning. It just moves a bit. Then, a second or two later my computer shuts off again.

After this process, pushing the power button will not turn on my computer until I wait another 3-5 minutes or so. Then, it will turn on again and the process repeats.

The problem shouldn't have to do with the new wireless card, because a) it was working at first, and b) I've taken the card out and tried to boot my computer up and the same problem still happens.

Unfortunately I didn't have my case open so I wasn't able to see what happened when it shut off. I'm wondering if it's possible that there's something wrong with my CPU fan, and the computer shut down due to overheating initially, and now it won't boot up because the BIOS detects that the heatsink fan isn't working?

Googling suggested that it might be a short, but I can't imagine that that's the case because I haven't changed anything around and it was working fine before for an extended period of time.

If it matters, I've been careful and using a wrist strap and such.

The only other odd thing was that after I installed the wireless card my computer made a strange noise when booting up instead of the normal post noise. It was sort of a weird "scratchy" electronic noise. Despite that, it booted up normally. When I restarted the computer once, it made the regular POST noise, and then I restarted a second time a few minutes later and it made the weird scratchy noise again. Then, after that time the computer died.

I went through the cycle of turning it on and observing it a couple more times, but I'm sort of afraid to try again because if it's an overheating problem I don't want to damage the CPU/mobo.

Any help greatly appreciated!
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  1. From your description, sounds like heat or psu.

    I assume you have a 4-pin fan connected properly to the cpu fan header on your mobo. And that you have done nothing in BIOS that would make the PC think YOU are controlling that fan.

    If you have a known working 4-pin or 3-pin fan, see if that fan will spin when attached to the cpu fan header and powering up the PC. If another fan will spin, the cooler fan is bad and needs to be replaced. The noise may have come from it.

    After a long cooldown period, open the case and remove the wireless card (last thing done is first thing undone). Then power up the PC while simultaneously giving the cpu fan a spin with your finger, as if you were trying to jump start it. That MAY get the fan started (but you'd still want to replace that fan).
  2. Thanks for the response.

    I did what you suggested. If I hook up a case fan to the CPU fan port, the case fan works fine.

    I tried spinning the CPU fan with my finger, and this resulted in the CPU fan spinning on its own, but only very slowly. The machine still shut off.

    So, the fan might be faulty. One other thing that I've noticed is that there is a ticking noise coming almost certainly from the inside the PSU. But the PSU shouldn't be bad if it's supplying power to the fans, should it?
  3. Minor correction - we now know the cpu fan is faulty :) Need to get something on that cooler that spins and cools before going any further.

    Note that for testing (and perhaps careful use) you can jury-rig almost any fan on a cooler. Maybe not with old hockey sticks and duct tape, but . . . well, get a fan on the cooler. And until you get a proper 4-pin replacement fan, make sure its spinning at 100%. BTW, which cooler are you using?

    A psu should not be making noise (except healthy fan noise). And having lights on, fans spinning, etc is not a sign of a healthy psu. The failure modes are many, and frankly most hardware issues resolved here are PSU issues. Is the ticking noise related to the speed of the psu's fan? Faster = faster, slower = slower?
  4. The PSU's fan seems to be going at a pretty much constant speed, but I don't really know if it's correlated with the ticking. But I don't think it is. The ticking occurs at pretty regular intervals and continual.

    Wouldn't it be sort of weird for my fan and PSU to go bad simultaneously? Unless my PSU caused other parts to go bad. Is it common for a bad PSU to damage other system components? Because that would be a pain.

    Anyway, I'm going to try 2 things tomorrow: use my friend's PSU try a new fan on the cooler, if I can get ahold of one. Might just swap one of said friend's heatsink to check and see if I can get my comp to boot up.

    You asked what sort of cooler I was using: I'm just using the one that came with my CPU, so I assume it's some sort of AMD cooler? It doesn't have a brand label it. Would I be better off with a coolermaster cooler or something? (at this point, I guess I would be better off with any other cooler, so long as it was working, haha.)

    Anyway, I appreciate your help. Hopefully I can get this resolved.
  5. Sounds inside a PC case can be deceiving - if its a ticking noise from your psu, you might be able to "feel" it.

    OK, you're using the stock cooler. Since you are in need of a replacement fan, if this repalcement cooler at $30 fits your socket . . . don't let the price fool you its a great cooler:

    Wierd to have two simultaneous problems? Yes, rare. But often you have one problem (eg ticking) and then later a fan bearing dies.

    Could the psu have done it? PSUs can and do damage parts. That's one reason we always recommend quality PSUs.

    But let's get the new fan/cooler installed, and do your psu test. That'll give us the data you need.
  6. Ok, thanks. I'll look into getting a quality cooler. I have a question, though. Isn't it a bad sign that I'm not getting any POST codes at all? Shouldn't I be hearing some sort of error if my CPU fan isn't working properly? Does the fact that I'm not indicate that my motherboard may be damaged? ><
  7. I don't know enough about your specific mobo and its settings to answer your question. Some mobos will do nothing without sensing the cpu fan.

    But we clearly need to fix the first problem and see if that allows us to get further . . . while watching the "ticking" problem.
  8. All right, looks like the worst has occurred.

    I hooked up my friend's PSU to my computer and it did the same thing: turned on briefly and then shut off. I unplugged everything from the mobo except the power supply, and powered on the computer. I didn't get a POST noise, and after about 30 seconds - 1 min after powering on it turned off. So, I assume that means that my mobo is dead. I don't know what else may or may not be dead, though. Since the CPU fan was dead, and the mobo is dead, I assume that the CPU is also probably dead. Not sure about the power supply, but since it's making the ticking noise, I assume it might be good to replace it.

    So, I bought all this stuff off of newegg, but since I had everything working I didn't keep all the packaging that came with it, which is bad because I didn't read their return policy until now, which is telling me I need all the original packaging to get an exchange. Ugh! Hopefully I can get these parts replaced under warranty...

    Well, this is no fun ._.
  9. Sorry to hear. Good luck with the replacements.
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