System crashes/shuts down, no BSOD, cause unknown

Good morning. About 6 weeks ago my system started to crash occasionally, often from one to several days between crashes. When it crashes it simply shuts down w/o notice as if I turned power off. Screen black of course, and no fans etc.. Doesn't seem to matter what programs are open. Of course all work not saved is gone.

Setup: GA-Z170-HD3P-CF/Bios F20; Intel Core i5-6500 @ 3.20GHz; built in Intel HD Graphics 530; Corsair Vengeance 16GB (2 x 8GB) DDR4 3000 (PC4 24000); Antex G500 case with Corsair CX series CX600M 600W power supply; Boot drive: SAMSUNG 840 EVO SSD 120GB; Storage drive: Hitachi Ultrastar 2TB 7200RPM SATA III; Windows 10 Pro, all updates current.

How do I go about diagnosing the cause? System was built last Spring and had run perfectly until a month ago.

Thanks for the help. The event log shows critical errors on times this crash has occurred. In each case on summary page it states there was a "kernal power" issue: EventID 41 and Task Category 63. I have no idea what that actually means except that the system shutdown "unexpectedly." Event viewer says "This error could be caused if the system stopped responding, crashed, or lost power unexpectedly." This occurred maybe 15 times sporadically since mid Feb.

So what would next step be? I looked over the more detailed info in Event Viewer and hadn't a clue what i was reading.

Thsnks, Denis

Did you make any recent hardware or software changes before the BSOD?
Most BSOD are related to misbehaving drivers.
The drivers can be identified, then uninstalled and new ones installed.
To reduce the number of drivers in use that are possible sources of the BSOD please place your computer in clean boot:

How to perform a Clean Boot in Windows 10 - TechNet Articles - United States (English) - TechNet Wiki


https://support.microsoft.com/en-us/...oot-in-windows

In clean boot you should have fewer or no BSOD.
If you still have BSOD then place your computer in safe mode with networking. And when you begin troubleshooting you may change to safe mode with command prompt.

Safe mode in Win 10 - Microsoft Community

Make sure that your computer is properly configured to collect BSOD files so that any future BSOD create minidump and memory.dmp files.

BSOD Finding and fixing them - Microsoft Community

You can download third party software such as whocrashed and/or bluescreenview which will give immediate information about the misbehaving driver or drivers.
Alternatively on this forum you can search for the minidump or memory.dmp files and attach onedrive or dropbox links for analysis.
It will be necessary that you are familiar with your computer manufacturers web site to download new drivers for you computers configuration and operating system.

Updating a driver. - Microsoft Community

"Did you experience power issues? Are you plugged into a UPS?
Did you check your PSU and all cables connections, since you've build the machine yourself?"
NO, no power issues at times of failure. I am connected to a UPS. I will open her up and go through all PS connectors (good idea, thanks). Then I'll get back to you. None the less i will get system setup for the minidump and memory.dmp files.

Thanks Zbook for you ideas. Problem with a clean boot etc is that I would then have a fairly useless computer for days: no antivirus or any other 3rd party program. Not practical if at all avoidable.
Also, I do not get a BSOD so I'm not sure the memory dumps would have anything useful. The machine simply shuts down instantly when this occurs. I have just downloaded whocrashed and will install.

Thanks guys, I appreciate your help,
Denis

There is safe mode, there is clean boot and there is quasi clean boot. The quasi clean boot is somewhere less than un-checking all of the boxes in msconfig. Performance actually increases as you keep off all the applications that are consuming CPU, GPU, disk, memory etc. Check out the quasi clean boot and then go more and more towards the clean boot. With the applications off at boot the boot time is faster. It takes longer to load the program that was off on boot but once it is on it generally is performing at a lower CPU, memory etc. Check it out. The benefit is you have fewer drivers in use and a reduced likelyhood of a misbehaving driver producing a bsod..