Question My new PC behave weirdly and Sometimes Reboot itself

[Jeckylll]

Pardon my lack English but while ago i bought new pc with this specifications :

Ryzen 3600 with stock cooler
Asrock Steel Legend b450M
Corsair vengeance ddr4 2666x2
2x 1gb sata hdd + 128 sata ssd
Aerocool lux 550 psu.
And using my gpu from my previous system inno3d rtx 2060.

So after few days my pc works fine and suddenly my pc restarting randomly (no bsod) during game but not all of them, I tried playing Assassin's Creed odyssey and it's run flawlessly even on ultra it's also working fine with ghost recon wildlands on ultra no restart whatsoever. But if i play skyrim it cause my pc to restart at certain places, also sometimes even steam causing pc restart when i open library tabs, discord won't even started. Turn out after few check my pc got infested with grenam virus, so i reinstall my windows and the virus is gone.
But the problem still there, i tried running memtest and no error detected but if run unigine valley on extreme HD preset my pc would restart after few seconds.

I tried to google my way out and found most of the answer of my problem is because my psu , so i RMA my psu and get a better one which is superflower leadex iii gold 650 w.
Buuut turn out the problem still happens, pc random reboot during steam library tab, unigine valley benchmark on ultra, discord won't open. Please help me I don't know what to do anymore 😔, the pc is not even 2 months old. I open the Event Viewer the log is kernel power 41 task 63, also theres plenty of DCOM and Kernel Event tracing error.

strangely yesterday I tried to change the thermal paste, reseating the the CPU Cooler, and changing my GPU pin cable and suddenly its works normaly. I tried the unigine valley benchmark with no crash and get to view my score, I have the picture to proof it but idk how to upload in here. So I play few games and I notice one of my hdd is not plugged yet. So I open my pc case again... and voila its back again with the error

To summarize what I already test :

1. Swapped My PSU
2. Clean Install WIndows and upgraded to the latest
3. Changed the termal paste on the CPU
4. Checked if the cable plugged properly
5. Did DISM checking found error
6. Few game crash, but furmark benchmark passes. Unigine Crashes.

Whats bothers me is what causing this error, which part is causing the error, thanks

 

[Lutfij]

Are you on the latest BIOS update for your motherboard? How old is the PSU? Did you reinstall your OS after creating a bootable installer using Windows Media Creation Tools?

changing my GPU pin cable
mind stating what you mean by that line? Did you use cables meant for another PSU on your existing PSU?

 

[Jeckylll]

@Lutfij strangely, i did updated my bios to latest version 3.20 from 2.90 hour ago, and my pc stuck on reboot after login.

I did reinstall my pc using both method. The problem still there

I meant my psu have branched gpu cable 2x 6+2, I tried to change again vice versa and the problem still there.

 

[Jeckylll]

So update, for my problem so I recorded a video of my steam library keep refresing until it reboot my system. For quick note the power didnt power down or I assume so becaue i didnt saw all of my rbg stuff turn off. Its not just steam, discord also doing this.. it will keep reloading itself until it rebooted my pc. Please someone heelp