[SOLVED] PC build is unreliable, shuts off, won't boot sometimes... help

[neonplants]

Hey, general question about diagnostics.
I built a PC last summer, and it's been a mess.
Lots of issues, replaced the power supply, motherboard and upgraded the CPU.
It still shuts down on its own sometimes, and 2/3rds of the time, it won't boot at all or goes into a power cycle loop. I end up taking out all the components, putting them back in the exact same way, until it magically all works again.
I've reset the BIOS, but I'm still pretty new to PC building and Windows in general.

How would you go about diagnosing these problems?
Every hardware test, breadboarding etc seems to indicate that the hardware is okay.
Not sure what to try next.

Parts list:

PCPartPicker Part List: https://pcpartpicker.com/list/ZQYft8

CPU: Intel Core i9-9900K (Standard Folding Box) 3.6 GHz 8-Core Processor ($369.99 @ Amazon)
CPU Cooler: Scythe Mugen 5 Rev. B 51.17 CFM CPU Cooler ($49.99 @ Amazon)
Motherboard: Gigabyte Z390 DESIGNARE ATX LGA1151 Motherboard
Memory: G.Skill Ripjaws V Series 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory ($146.26)
Memory: G.Skill Ripjaws V Series 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory ($159.99 @ Newegg)
Storage: PNY CS900 500 GB 2.5" Solid State Drive ($59.80)
Storage: Samsung 970 EVO Plus 2 TB M.2-2280 NVME Solid State Drive ($319.99 @ Amazon)
Storage: Seagate Barracuda Compute 2 TB 3.5" 7200RPM Internal Hard Drive ($55.49 @ Walmart)
Storage: Seagate BarraCuda Pro 10 TB 3.5" 7200RPM Internal Hard Drive ($320.00 @ Amazon)
Video Card: Gigabyte GeForce GTX 1650 SUPER 4 GB WINDFORCE OC Video Card ($173.99)
Case: NZXT H510i ATX Mid Tower Case ($99.99 @ Amazon)
Power Supply: Corsair RM (2019) 750 W 80+ Gold Certified Fully Modular ATX Power Supply ($124.99 @ Best Buy)
Custom: Elgato Game Capture HD60 Pro, stream and record in 1080p60, superior low latency technology, H.264 hardware encoding, PCIe ($149.94 @ Amazon)
Custom: Elgato Game Capture HD60 Pro, stream and record in 1080p60, superior low latency technology, H.264 hardware encoding, PCIe ($149.94 @ Amazon)
Total: $2180.36
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2021-03-10 15:19 EST-0500

 

[Ralston18]

Any temperature problems?

Look in Reliability History and Event Viewer for error codes, warnings, and even informational entries that correspond with the shutdowns.

Simplify the build: roll back to just the boot drive ( C being connected. Determine if the problem continues.

If not add another disk drive or other component. Test, and determine if the problem continues.

Key is to change only one thing at a time and allow some time between changes to ensure that all is indeed well.

Start with a scaled back basic system that you can be certain is working as expected and no errors.

Then start adding components one by one.

 

[neonplants]

Any temperature problems?

Look in Reliability History and Event Viewer for error codes, warnings, and even informational entries that correspond with the shutdowns.

Simplify the build: roll back to just the boot drive ( C being connected. Determine if the problem continues.

If not add another disk drive or other component. Test, and determine if the problem continues.

Key is to change only one thing at a time and allow some time between changes to ensure that all is indeed well.

Start with a scaled back basic system that you can be certain is working as expected and no errors.

Then start adding components one by one.

Thank you! Pulled all USB drives and devices and it booted.
At least at once time when it was acting up, the BIOS said the system temperature was super low. Can't remember what it was, but well below problematic temperatures.
So I don't think it's that.
Will continue with removing devices and adding them, and will report if I learn anything. Appreciate it.

 

[punkncat]

I ran into a recent issue with a system I built and use having random shutdown, weird boot issues, etc. Turned out to be a failing HDD. It made no noise or gave any other indication that anything was wrong with it and was not the boot drive. I probably would not have discovered the issue without doing a complete teardown/breadboard.

I would assume you watch Carey Holzman considering your CPU and fan choice. (lol)

 

[rickypicky5]

Low temperature in BIOS, prior to booting into Windows, is nice but not that telling. You want to download/install something like HWINFO or HWMONITOR and run it while in Windows while you're doing things (surfing, etc...) that you normally do when the system shuts down.

The i9-9900K can get pretty toasty if it's not properly cooled.

 

[neonplants]

I ran into a recent issue with a system I built and use having random shutdown, weird boot issues, etc. Turned out to be a failing HDD. It made no noise or gave any other indication that anything was wrong with it and was not the boot drive. I probably would not have discovered the issue without doing a complete teardown/breadboard.

I would assume you watch Carey Holzman considering your CPU and fan choice. (lol)

How did you diagnose the failing hard drive if it wasn't exhibiting any symptoms?

Also! never heard of Cary Holzman, guess I should look him up if I independently arrived at the same thing he's into ¯\(ツ)/¯

 

[punkncat]

How did you diagnose the failing hard drive if it wasn't exhibiting any symptoms?

Also! never heard of Cary Holzman, guess I should look him up if I independently arrived at the same thing he's into ¯\(ツ)/¯

Luck while chasing something else.