This sounds like it was all put in the case and hope it works. So back to the motherboard box with the motherboard in the box (it works as a test bench here) and just one stick RAM, the PSU, CPU+HSF and the video card. No drives are needed.
If that won't power up and stay up then we are done as we are looking at the possible bad part or parts. Most folk RMA that lot and start over.
If it does stay up then it could be a motherboard mounting issue. I still run into machines with extra motherboard mounting posts. And yes folk will argue it worked fine for days to years.
Brand new PC build worked for 2 days and even got in a night of gaming. Next morning the PC started for about 4-5 seconds then turned off. I flipped the power switch off and on then pressed the power button on the case and this time it started for about half a second before turning off. There are 2 diagnostic lights that turn on when turning on my PC, the CPU and DRAM lights. This is my first PC build and have triple checked everything included removing and reassembling just about everything.
When contacting my motherboard's support, they recommended clearing CMOS, which is what I did, I removed the battery and cleared CMOS which seemed to work at the moment. The PC was able to stay on for multiple minutes allowing me to get into the CMOS setup and load Optimal Defaults settings. I got to my Windows login screen thinking it was fixed but once again it shut down on itself.
Also, the first thing I did was testing my power supply with a paperclip and that seemed to work. I also tried different RAM slots and with one RAM stick, which didn't work. I don't know much about PCs as this is my first build, but I made sure everything isn't visually damaged, is seated properly, and all cords are plugged in all the way.
Every time I try to turn on my PC, it stays on for not even half a second before turning off, while it is on, the fans spin and the 2 CPU and DRAM lights are on. But, one time out of the blue I turned it on and it managed to stay on for about 7 minutes. This was the morning after I cleared the CMOS. When powering on, the fans spun up and once again the CPU and DRAM lights appeared. They stayed for a few seconds then went away, followed by the other 2 diagnostic lights, the VGA and BOOT. Those turned on for a few seconds and disappeared, leaving no lights on and my PC on. When it turned on, I got a message saying there are some repairs that need to be made, which only took about 30 seconds. Then, I logged into windows and opened up Chrome thinking the problem had fixed itself. But my PC turned off and when trying to turn it back on, it shut off immediately.
As I said, I'm inexperienced and now confused. I'm not really sure what the problem is and don't believe I've done anything wrong. Can anyone please help out with some suggestions or at least help identify what's going on? Oh and since this is my first build I don't have any spare parts lying around to swap in and out. Thanks.
(I didn't overclock anything or messed with any of that other than using an XMP Profile for the RAM to get the 3600 speeds)
Video I took as PC turned on during the 7 minute run: https://drive.google.com/file/d/1S9lhPLFbw9KNdtucRm4JpUppXqLWUlXQ/view?usp=sharing
CPU: AMD Ryzen 5 3600X 3.8 GHz 6-Core Processor
Motherboard: ASRock X570 Phantom Gaming 4 ATX AM4 Motherboard
Memory: G.Skill Ripjaws V 16 GB (2 x 8 GB) DDR4-3600 Memory
Storage: Intel 660p Series 1.02 TB M.2-2280 NVME Solid State Drive
Graphics Card: Gigabyte GeForce RTX 2060 6 GB OC Video Card
Power Supply: Corsair CXM 550 W 80+ Bronze Certified Semi-modular ATX
Sorry for lengthy post, I tried to be as detailed as possible. This is also my first post.