Question PC randomly shuts off but fans and cpu sti running

[CyberBird]

Hello,

I recently changed my motherboard to a new one after encountering boot problems with my last one. After installing it, i booted it up windows only for it to shut off 1 minute later. This happened a few more times with different times before it shuts off, and in one occasion it restarted. The keyboard and mouse LEDs both switch off and the screen too. I can also see from the LEDs on my mobo that the boot is off so windows just shut down.


System Specs:
Ryzen 5 1600
Gigabyte Aorus B450 Elite (new mobo)
G.Skill Flare X (2x8GB)
GTX 1060 6GB
Kingston 120gb ssd and wd 1tb hdd
Seasonic S12ii 500w psu

What i tried so far:
I booted it into the BIOS and left it for a while and it didn't shut off
Reseated the RAM and made sure all the cables are plugged securely
Changed my SSDs SATA cable
checked the SSD Health from Kingston ssd manager but everything seems fine
Ran memtest and got no erros

Then,
I tried reinstalling windows but here is where I messed up. When i booted it from the USB drive everything seemed fine and no shut offs, i decided to do a clean install and deleted the previous version of Windows. However, Midway through the install it turned off....


I really don't know what to do here. I suspected it might be a bad PSU or it was taking too much power but there is no reason for that since i never even had the time to start a game or anything demanding. And also it worked fine in the BIOS and the 4 hour memtest so i don't think its a PSU issue.

RAM is also fine and I literally just upgraded my ram stick to the g.skill flare 2 months ago.

Please tell me what you guys think and what should I do now. Any help is appreciated.

 

[Lutfij]

What was the make and model of the old motherboard? Are you on the M12II or the M12III from Seasonic? If the former, how old is the unit? Can you enter into BIOS and remain there indefinitely?

 

[CyberBird]

What was the make and model of the old motherboard? Are you on the M12II or the M12III from Seasonic? If the former, how old is the unit? Can you enter into BIOS and remain there indefinitely?

Hello,

Previous motherboard was Gigabyte AB350M- GAMING 3.

I have the Seasonic S12II 520W 80+ bronze PSU. It has been with me since February 2018 so a little over 2.5 years.

I left the BIOS open for an hour and it didn't close, and memtest for 4 hours. The longest time i was in windows before it shutdown was 20 minutes so it's safe to say I leave it there indefinitely. I'll try again now aswell.

Update: I tried reinstalling windows from USB again and got this error:
Stop Code: IRQL NOT LESS OR EQUAL

 

[CyberBird]

What was the make and model of the old motherboard? Are you on the M12II or the M12III from Seasonic? If the former, how old is the unit? Can you enter into BIOS and remain there indefinitely?

Another Update: i tried reinstalling windows again, it just shuts off, no error this time. However, i noticed something. The motherboard has 4 LED lights for BOOT, CPU, RAM, GPU. When the pc shuts off, the RAM and CPU lights both start blinking in alternating intervals

 

[CyberBird]

Apparently this means they're not working properly? But I checked the RAM and it was working fine. Im very confused.