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Random and instant computer reboots


Just recently i have problems that computer suddenly reboot itself (and after a few reboots it sometimes shuts down without rebooting again automatically).

This happens during windows loading screen, login screen, playing graphic intensive games, surfing websites.

When it does run, everything seems to run fine: internet, sound, all programs, graphics cards, monitor, etc.

- No smoke detected when rebooting occurs and probably in all occasions.

I do noticed that after it reboots the first time, the second reboot arrives earlier than the first (that is, first time it might take 15 minutes, but if it reboots and continue it usually reboots within 15 seconds.)

I monitored motherboard temperatures (10 points temperature sensor on MB), cpu and gpu and they can all run intensive tasks like games with no temperature problems (I use liquid cooling nxzt kraken)

- No software changes were made when this happened. Using win 7 32-bit. Also no hardware changes were made as well.

Do you think:
1) It can be short circuit in motherboard that causes this spontaneous rebooting?
2) My PSU is almost 6 years old. Can a "nearly" failing or "slightly" faulty PSU cause this spontaneous rebooting? I would like to use the word nearly or slightly because it can still run my computer for tens of minutes.
3) Short circuit in some components?

Thank you for any advice at all.

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Clarification Request
Have you checked for viruses & malware?

In reply to: Random and instant computer reboots

Have you booted to Safe Mode and checked for viruses and malware? That's one possibility. Are you current on Windows maintenance? That's another. Have you checked for bad sectors? Still another. Have you run SFC and checked for corrupt files? You could also look at the system event log for entries flagged "error". You didn't mention any of these, so I just did. PSUs do age over time, so that's just one more thing to check out. Multimeters are inexpensive. I bought one for $15 a couple of months ago. And of course with a 6 year old computer, bad caps are another possibility. You just have to eliminate the possibilities one by one 'till you find the problem. Of course a new PC would solve the problem too. Grin
Good luck.l

All Answers

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Most Likely PSU

In reply to: Random and instant computer reboots

Power supplies are a very tricky creature, especially at the age of 6. Like was posted above there are several reasons this could be happening from failing memory to corrupt Windows up to and including the Power Supply.

Taking that this is a desktop I would look first at the power supply, the answer is yes in a large majority of instances the power supply could be failing and causing a reboot especially under load. Given the age of the power supply this is where I would look first. If your memory is as old as the power supply then checking this is also highly recommended. Using Memtest86+ from a bootable media and running multiple runs to test for bad or failing memory is of course the cheapest in the diagnostic process. More times than not the symptoms you are describing leads to a failing power supply in my experience

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Just a couple of troubleshooting ideas

In reply to: Random and instant computer reboots

What you first should do is rule out either software or hardware. If you boot the system and enter the BIOS set up screens and just monitor it for a while, the CPU temperature should climb above the level it does when Windows is running and idle. If it reboots at that point, you can rule out Windows, malware, etc., and you're stuck with looking at hardware. You then remove non essential items one at a time and wait it out again. It also doesn't hurt to unplug everything and reseat connectors. Corrosion or ill fitting connections can cause any number of problems. If you have both on board video and an add in card, pull the card and run on the MB video. If your PS is low on ability to deliver enough current, removing hardware that draws from it might help disclose whether or not it is the culprit.

Anyway, this is how we narrow things down. Long ago we had a troubleshooting method called the "half split" which just meant we attempt to start from the middle and work outward searching for the first failure point. Where hardware meets software is a good place to begin. We do that and the simple things first rather than just throwing ideas at a problem.

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In reply to: Random and instant computer reboots

Hi everyone,

First of all really thanks for all great advice.

I think i may have found the source of the problem.

Yesterday i went out to change PSU. Since i thought it possibly was a PSU problem I tried to get one which perhaps is reviewed by many to be quite really good - corsair ax860i.

However, that did not solve the problem yet. It still rebooted and sometimes shut down automatically.

Finally I unplug many things like Steven Haninger said - and test each component.

What i found out is that I might have a bad ethernet cable (an old one).

Now i changed the cable into new one i just bought (high quality one). No more shutdowns, no more reboots - so far.

It 's been around 10 hours of operation now with no problem. But if you have any comments on this please post them (if you think my conclusion might be wrong or anything).

But i still think i need to continue and wait and see if there will be any problem from now on and perhaps give some more posts to help anyone in the future who might face this problem.

Again, thanks to everyone here. Advice were great and fast Happy

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Good to hear and Thanks for the feedback.

In reply to: Progress

It closes the issue and may help another user with a similar problem.

Let us know if the disposition changes.


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