Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Having a bit of an issue here. Basically I just built a new PC with the following components:

Before purchasing, I checked all CPU, motherboard, and memory specs to make sure that all items were compatible. My issue is that the machine randomly shuts off -- no BSOD, just powers off. There is no single activity or time interval that triggers it -- it simply shuts off at random. I have performed the following tests in order to mitigate the issue:

  • tested the power supply and it checks out
  • performed several clean installs
  • run memory tests, "burn in" tests, etc using UBCD 5.03 and everything seems to check out.

However, these random crashes continue, and are quite frustrating. Interestingly, if I do absolutely nothing (i.e. leave it running overnight without touching it) it continues to run with no issue. If anyone has any suggestions about what path to take next as far as diagnostics, I'm all ears. Otherwise it looks like RMA time.

EDIT: One thing I forgot to mention is the fact that the PC won't power back on unless I first switch off the power supply for about 30 seconds. I'm not sure if this is due to the manner in which Windows randomly shuts down, or due to a fault that is wholly that of the power supply. Thoughts?

share|improve this question
Do you get a minidump that can be analyzed? Being able to figure out if there is a faulting module, consistently, would go miles for figuring out what it is. – vcsjones Mar 7 '11 at 2:14
Have you checked out the HDD or processor temperatures? It is possible that something is getting overheated, prompting the shutdown. – MaQleod Mar 7 '11 at 2:55
No, no chance for a minidump -- it simply powers off. As for temps, I've tested and checked everything. Unless something is being misreported all temps are well within acceptable limits. – humble_coder Mar 7 '11 at 3:18
This may sound silly, but it happened to me. One of the cables going to my motherboard kept falling and getting caught in a fan which would stop turning and the whole thing would shutoff. – a sandwhich Mar 7 '11 at 5:57
I was wondering if you ever figured this out, I have a notebook exhibiting similar symptoms except I can boot to Windows or Linux normally but if I put it in safe mode to run a virus scan with minimal software running or try running diags off of UBCD the system will randomly shut down, at times when it does it with safe mode it acts like it is overheating though it isn't. – RadG Aug 25 '11 at 12:18
up vote 0 down vote accepted

I would guess it's either the power supply or the motherboard. Double-check that you've made all the correct power connections on the mobo. Some motherboards require two connections from the power supply. You didn't mention what video card you have, but if it's one that requires a separate power connection, make sure it's connected properly.

share|improve this answer
Thanks so far. Actually I'm using the on-board VGA for the time being. Trying to eliminate all variables. And I've attached both connections to the motherboard. I've been scouring the motherboard and (perhaps I'm being paranoid, but) it looks like one of the traces near the proc might be sliiiiiiiiightly damaged/cut -- although I'm not sure how as I haven't been digging around. Wouldn't a damaged trace manifest more consistently though? Again, maybe I'm just trying to find something to blame -- I'm fairly frazzled atm. – humble_coder Mar 7 '11 at 1:53

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.