PC hard resetting randomly

[Sam5127]

Issue:

PC hard resets randomly. By hard reset I mean, suddenly, screen goes black and all lights and fans turn off, then after half a second then lights and fans turn on and the PC boots up. It started happening all of a sudden, I didn't change any hardware. I'd like to mention that when a hard resets happens, mostly the lights/fans turn on and turn off very quickly twice or thrice then they stay turned on for a while and pc boots, although sometimes they turn off and turn on once only.

 

Frequency of occurring:

It started last year in November I think, happened quite often then, like 5-6 times per day then in a week or two, it stopped happening. Then it started happening last month, same frequency, 5-6 times a day then stopped. Now it started happening again from this week with the same frequency, 5-6 times per day.

 

Solutions I've tried:

• I have two RAM sticks, tried it with either RAM stick and the problem didn't go away.
• I connect my power strip to a voltage regulator which then connects to the wall socket. I tried connecting the power strip directly to the wall socket but the problem didn't go away.
• Disconnect the case's power button and using a metallic paper clip to turn on PC to see if it was a faulty power button but the problem didn't go away.

 

Solutions I've been recommended:

• Someone told me they had hard resets and artifacting recently and it turned out it was their GPU but I don't have artifacting, only hard resets.
• RMA my PSU.

 

Specs:

• i5-8400 CPU
• Gigabyte RX 580 GAMING 8GB Graphic Card
• Asus Strix B360-F Motherboard
• Corsair Vengeance 8gb 2666 mhz RAM
• ADATA 8gb 2666 mhz RAM
• Corsair RM750x PSU

 

Please help, thank you.