Is my PC failing? How can I check what is wrong? Boot frozen

Part of me says it's Windows 10 'having one of those days' as I experience the same problems on both my old XP computer and my main computer, an overclocked AMD Ryzen 3800x.

I do a normal 'power off' of both computers every night. So I know that I get a full POST (Power On Self Test) and 'fresh copy' of Windows and its device drivers every morning. I'm a techie, so I SHOULD be able to figure out what the problem is, but thus far, have not taken the time to try.

In my opinion, there's a number of possibilities for the problem. But the 'real' problem, for me, is the inability to reliably 'force' the problem to occur. Unless I can make the problem occur when I want it to, how can I ever know I fixed it and not 'fixed' something that wasn't broken in the first place. So, until it happens every time (usually, 3rd try to power up is the charm) I'm content to merely going into panic mode for a minute or two every now and then.

As for possibilities...here's my list, in no particular order:
1. RAM stick failure - I've had that happen twice on my own computers in the 30+ years I've been building my own and others computers. There's no 'standard' symptom when a stick of RAM is failing. It could be a blue screen, scrambled images on a screen, damaged image files (saved from Photoshop, for example), and yes, failure to fully boot up. Most users, myself included, set the BIOS for 'fast boot' which means only a minimal RAM test when booting. One idea would be to change that option, but it may add 10-20 seconds to your bootup time. Another is to download a RAM 'checker' app and let it run for an hour or so with nothing else running. The latter would give a clear indication of a RAM failure.

2. Failing battery. Those CR2032 batteries on the mobo don't last forever. When they do get weak, most often, the boot up will force me to the BIOS screen to set the date, etc. It's the battery that causes the BIOS to 'remember' its settings, so a failing battery necessitates re-setting everything, usually to 'default' values, but the date and time has to be set. If you have to set the date and time when you boot (not always necessary to enter BIOS to do it), the battery is dead. On my XP box, I'll do that for a while until I get the energy to open it up and replace the battery.

3. Failing boot drive (C:). Both hard drives and solid state drives WILL FAIL eventually. Problems tend to show up with slower-than-normal disk activity, not counting 'bloatware' and/or too small RAM, as BIOS will try re-reading or re-writing a bad spot/sector a good number of times before it gives up and either writes it to a 'spare' sector or will cause a blue screen of death (BSOD) when reading. To check your drives, download a free copy of 'clear disk info' (Google it) and look at the 'critical attributes' highlighted in green for each of your drives. Note that -some- reallocated sectors are OK. How big -some- is depends on who is doing the interpreting. Note that the 'failure predicted' value (yes/no) above is probably the best gauge of overall drive health. Also, failing secondary drives will delay the boot up while it retries multiple times, but not stop it dead. Windows will simply not 'see' that drive when you try to access it.

4. Slowly corroding (ie, rust, if it were steel) electrical contacts be it cables between mobo and devices, or even contacts for the video card or RAM. This would be most common in humid environments. What happens is that some electrical signal drops below an expected voltage, so that process fails. On rebooting, that signal is OK. Simply re-seating every cable and removable board & RAM would cure the problem. Alternatively, give it a good 'whack' with the heel of your hand might be sufficient to cure the problem. I've even kicked my tower computer with the side of my foot a time or two as well...typically out of anger rather than a perceived computer problem.

5. Poltergeist. It's haunted. Buy a new computer.

EDIT: I should mention I DID have a motherboard failure about 2 years ago. It was a used mobo and used processor I built for church that gets used only in the production of CDs of each Sundays' sermons. Other than fans spinning at power up, nothing else happened. It was 100% consistent. I first thought it was either the 5v or 12v 'side' of the power supply, but it wasn't. I replaced the CPU and that didn't fix it either. Ultimately, replacing the mobo did the trick. As the computer was in an enclosed cabinet with only a small area 'open' at the rear, I figure the computer became overheated slightly on multiple occassions until it died. The overheating was solved by installing a full-slot front-facing exhaust fan in an open bay on the computer.