Question Possible to fix a maybe dead CPU?

Dec 8, 2020
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Radeon 570 gpu
Ryzen 3600
MSI Ryzen 450 a, can't remember name of the other MB



SoSo I bought a Ryzen 3600 over a month ago and everything worked fine no over heating etc. Last Friday I go the shop come back and I see my computer going into sleep mode (only been a couple of mins so was like wtf). Anyways ever since then there has been no power going to the monitor mouse or keyboard although everything turns on as if it working and the cpu even heats up. My motherboard had no led to tell me the problem I thought it was dead motherboard at first so I bought a new one which came today. Exact same problem but this motherboard does have led lights saying it's a cpu problem. All the pins are straight and it looks all good physically (maybe tiny bit of thermal paste got on it not sure if that would break it) . Anyone have any idea what could be the problem and what a fix could be?
Also I've tried the PSU HDD and Graphics card in other MB and they worked not the RAM but tried the 1 slot technique etc in bother motherboards