Question Sudden instability on new system - can't boot

[Applin]

Hi everyone, first message here but I have been reading for a while in preparation for my first PC build! Thanks for all the good advices.

So I just finished my first PC build, and was happy that everything was working fine. For around two days, everything was A-OK. Now after two days, suddenly, it really has a problem booting. I have a GIGABYTE B550 AORUS PRO AC and it has four red LED for problems with cpu, DRAM, VGA or boot. Now on startup, most of the time the cpu light gets on immediately and only the GPU fans spins (no POST). But sometimes, other things happens. Once in the last few hours, it did POST and boot to windows but shut down after a minute or two with the DRAM light on. Or sometimes some of the four red LED flickers and end up on the DRAM or VGA. That kind of stuff...

Things I have tried:

• Checking my Power Supply. I do own a multimeter and know a bit about electronics. I checked the voltage on my PSU connectors (CPU, 24pin, PCI) and there were all within the acceptable range.
• Changing DRAM slots (tested all of them)
• Booting without GPU
• Clearing CMOS
• Removing and replacing the CPU with new thermal paste
• Disconnecting all fans but CPU cooler before booting

** I have tried to qflash the bios, but didnt seem to succeed. The qflash LED never lit up upon trying with a FAT32 formatted thumb drive with last BIOS version inserted in the correct USB slot.

It seems that if I left the system off for a couple minutes, or hours, it is less instable when I turn it back on. Or at least, it is not the CPU light that gets on. It seems that the longuer I leave it powered off, the better it gets. I have read stuff about static charging up? The weather is kind of humid, could it be that and if yes what can I do? Or is it something else completely? Any help solving this problem would be greatly appreciated . Again, I remind you that the system was working OK and the instability and failure to boot started without touching any components.

My full system spec:

• GIGABYTE B550 AORUS PRO AC
• AMD Ryzen 5 3600X
• Stock Wraith Cooler
• G.SKILL Ripjaws V Series 16GB 288-Pin DDR4 SDRAM DDR4 3200 (x1, just a single stick)
• EVGA 500W 100-W1-0500-KR 80+
• ASUS TUF Gaming GeForce GTX 1660 SUPER
• WD BLACK SN750 NVMe M.2 2280 500GB
• A couple of pwm RGB fans

Thanks a lot in advance.

 

[Applin]

UPDATE: my computer did boot to windows again, but after a couple minute, crashed, with the CPU red led lit. But something strange was going on, it seemed like it tried to go back on, powering on and then shutting down immediately on multiple occasions. I switched off the PSU to stop it ... on the next boot, a few red lights flickers and then stopped on CPU and all the fans stopped (beside the GPU, including CPU cooler).

UPDATE 2 : After a few cycle of "shutting down-waiting-powering back", it is getting a little more stable. I can access windows more frequently on startup and it takes longer before crash/shutdown. It is so random, I have no idea what is going on.