Computer not POST-ing

[adamgasth]

So, I was playing battlefield V and then my computer randomly turned off. Naturally, I turned it back on and then I realized that my fans aren't spinning. Most of them anyway. And the RGB was just as inconsistent. Front fans were off ( both rgb and the motor) while the top fans' rgb was on. That might be because the top fans' rgb is connecte through an rgb header while corsair link controls the top fans. Anyway, I removed one ram slot and it magically turned on again. A while later though, the same thing happened. But this time reseating ram didn't help. The weird thing is that gpu's rgb and rams rgb works. I thought about it for a wihile and narrowed the problem to three possible scenarios: 

1. Possibly dead cpu thanks to power outages I and previous sudden power losses. The motherboard speaker would however tell me if there was a bad component. Unfortunately, my motherboard didn't come with a speaker and I didn't buy one. With that said it would probably be useles anyway; my motherboard beeps during post. 
2. Bad PSU. I am using a 550W psu to power ryzen 5 2600X and GTX 1070ti. I work as a computer mechanic and I have noticed similar behaviour with the restarts in computers that have insufficient power supplies. But It night just be enough to power it. You tell me
3. Bad motherboard. I think this is pretty self-explanatory.

Here's the list of my computer's parts:

1. Asus x470-f 
2. Ryzen 5 2600x 
3. Gskill tridentZ rgb 2x8Gb 3200Mhz
4. Strix gtx 1070ti
5. Evga supernova 550w G3

So what do you think is the cause?