Question PC shut down automatically a few times, then stopped POSTing altogether ?

[rxy]

It's a 2019 built computer, so I turned on the PC opened a few folders and it shut down automatically two times then it didn't happen again so I played for a few hrs...then I came back this evening, turned it on again and it booted to the desktop but the keyboard and mouse neither lit up nor worked so I restarted it.

After that it didn't POST, the cpu light on my motherboard is lit red.
Things I've tried:

• flashed the bios
• cmos reset(by taking out the battery)
• realigned the cpu and tried flashing again
• removed all components except the 24pin and 8pin and flashed bios again
• tried booting with 1 ram stick

nothing worked and the cpu light was on all the time.

Specs:
MBD: MSI X570 A Pro
CPU: Ryzen 5 3600X
GPU: RTX 3060
PSU: Antec NE650M GB

 

[CountMike]

It's a 2019 built computer, so I turned on the PC opened a few folders and it shut down automatically two times then didn't happen again and I played for a few hrs...then came back this evening turned it on again and it booted till the desktop but the keyboard and mouse neither lit up nor worked so I restarted it.
After that it didn't post, the cpu light on my motherboard is lit red.
Things I've tried:
flashed the bios
cmos reset(by taking out the battery)
realigned the cpu and tried flashing again
removed all components except the 24pin and 8pin and flashed bios again
tried booting with 1 ram stick

nothing worked and the cpu light was on all the time

SPECS:
R5 3600x
rtx 3060
msi x570 a pro
Antec PSU NE650M GB

Next thing check or replace PSU

 

[rxy]

Next thing check or replace PSU

I don't have access to one rn... it'll be a few days before I can take one from my friend, will update if it works

 

[rxy]

Next thing check or replace PSU

UPDATE: I checked with another PSU, same problems, the CPU isn't heating up as well. I also checked with another ram stick(all slots) so that's not a problem, checked the CPU on a different motherboard and it works like normal, so I hate to say it but the only thing left is the motherboard.

I don't want to shell out on an expensive motherboard since I'm going to get a new PC, probably by next year. I just want to know if a B-Series would be fine for this build since I'm not going to be upgrading it. Any recommendations would be appreciated

 

[CountMike]

UPDATE: I checked with another PSU, same problems, the CPU isn't heating up as well. I also checked with another ram stick(all slots) so that's not a problem, checked the CPU on a different motherboard and it works like normal, so I hate to say it but the only thing left is the motherboard.

I don't want to shell out on an expensive motherboard since I'm going to get a new PC, probably by next year. I just want to know if a B-Series would be fine for this build since I'm not going to be upgrading it. Any recommendations would be appreciated

For 3600x even A320 would do let alone any b550.