Computer randomly shuts down. What to do?

Question

Solid State Drives

Good time!
There is a home PC, i5, ssd, and so on ...
Everything was fine, but not so long ago, the computer began to turn off spontaneously. It can work normally for a week, or it can turn off a couple of times in the evening.
What to do? Where to begin? Tell.
Thanks in advance.

Answer 1

Check for viruses, maybe something malicious is worth it. Takes and turns off the computer)

Answer 2

  Start with temperature control, otherwise you can guess a lot without system logs.

Answer 3

1. Look for a problem in the wires and power connectors (I had a case when the motherboard power connector was to blame, the power supply switch-on contacts were slightly larger and therefore there was a bad contact). Also, make sure that the processor cooling is well fixed.
2. Try to do a stress test, watch the temperature and voltage. Test for 10-20 minutes
3. If the stress test is successful, but it still turns off - look for a problem in the system. For example, you can change the OS for a while (put it on another hard drive, for example)
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In general, it seems to me that only the PSU can be naughty.

Answer 4

What to do? Where to begin? Tell.

It is stupid to open the case and look with your eyes - most likely, the processor heatsink is clogged with dust. Clean it, and the whole body at the same time, with a brush and a vacuum cleaner.

Answer 5

Here is the last log before shutting down at 0:00: The "Microsoft Shadow Copy Software Provider" service has transitioned to the Stopped state.
And here's what after I turned it on: The previous shutdown of the system at 0:31:43 on ‎10.‎01.‎2015 was unexpected.
And here is the temperature:

Answer 6

The problem is probably hardware, very possibly related to overheating. But as you can see from the question, before that the computer worked fine. It means that something either burned out, flew out, somewhere there is a bad contact, perhaps somewhere the contact oxidized and a short circuit along the wires, it is also desirable to clean everything from dust. Check the dust on the CPU, clean the dust. As advised, measure the temperature on the south and north bridges. Measure the temperature on the CPU. Look at what is set, what are the temperature limits in the BIOS for rebooting and shutting down. Also, shutting down and rebooting may be due to the instability of the RAM (I also met this from experience), I recommend testing the memory with memtest86+.
Also pay attention to what kind of operating system you have, if Windows (it seems to be from the screenshots), then check everything for viruses. Download a fresh portable antivirus program, in safe mode, check all disks and memory. Analyze logs. In the most extreme and tough case, if the system began to slow down, it may be possible to reinstall the system altogether or switch to Linux.
Deal with hardware and software comprehensively, analytically comparing the results, and your "patient" will gain a new life if you prescribe the right mixture for him! :) Good luck!

Answer 7

It also makes sense to check the PSU. I had this recently, the computer spontaneously turned off sometimes. The PSU is already old, and although the capacitors did not swell, something in it was already working wrong, and, apparently, the voltage was sagging. After replacing everything works great.
Not the fact that you have the same thing, but if other options do not help, see the BP.
You can watch the voltage according to monitoring programs, but it is practically useless. Ideally, if there is a "free" PSU (for example, rent it from another PC for a while), connect it and see if it helps.

Answer 8

Is the mains voltage normal? may jumps