Question PC won't POST, fans blare, tried almost everything

[Hobothesis]

At first the pc would get to the loading windows screen then reboot, then boot fine into windows. Did this for about 3 days. After that when I powered it on the fans would just start going and no post, no display, and keyboard/mouse wouldn't even light up. Figured it was mobo so I got one. First power on it would do the normal 'fans blare but nothing' then on forced power off then on it would boot. Then it all happened again. Tried new ram and same deal (yes, I even tried reseating/using 1 slot at a time, etc and nothing changed) so I figured maybe there's a short in the case or something so I breadboxed it. First few power ons it wouldn't do anything. Afterwards the fans would go on and after a longer amount of time compared to a normal 'working' bootup I saw the keyboard/mouse lights going then it went into the bios. Turned off and put the ssd in and booted to windows. Figured since I had it all out to reseat/check the cpu. Put everyting back in the case and it booted up. Kept it going all day, played some games, everything was working just like normal. No higher temps than normal, no weird noises. Then I was watching a vid on Youtube and it just randomly shut off and tried to reboot; but it's back to the fans just going. I've done numerous cmos resets, even followed someones total cmos reset on this forum by pulling the battery out for like 10 mins, putting a jumper cap on the prongs, etc. Could it be the PSU? I had an old Diablotek 450w laying around (it's old and honestly not sure if it even works right) and it would still do the 'fans going but no post/display.' Original build ran for just over a year before this happened.
Original build ran for a little over a year before this problem occured.

CPU Ryzen 5 3600 GPU GTX 1660 Super OC edition Mobo AsRock b450-HDV R4.0 RAM 16gb (2x8gb) G.Skill Ripjaws 3600 PSU EVGA 100-W1-0500-KR 500 W1

Ram I had in when it started doing this, if it matters, was T-Force Vulcan Z 16gb(2x8gb) 3200

Nothing in this system is overclocked, I've even tried swapping out the 1660 with my old 1050Ti and same deal. Used the 1050Ti on the breadbox as it's lightweight and I know it still works (currently on my old pc, just swapped the sdd over here lol, it's so slow =( i7-870 ugh

 

[DAPUNISHER]

It would be worth trying another, known good, PSU, to rule it out. My prime suspect is the board though.

 

[Hobothesis]

It would be worth trying another, known good, PSU, to rule it out. My prime suspect is the board though.

Why do you think it would be the board? I replaced it with a brand new one and it still does it. When it does decide to work, everything operates completely normal.

 

[VirtualLarry]

My prime suspect is the board though.

Yeah, those boards are ... poor quality.
Not all ASRocks, but I had some of their B350M Pro4 boards, and they were kind of dodgy.

Edit: I should clarify, I mean that on a relative scale; those are entry-level boards.

 

[DAPUNISHER]

What do you know, Hobo?

 

[Hobothesis]

What do you know, Hobo?

Watched a 20min vid on PSU diagnosing and one that tends to slip past people is my exact scenario. Where you hit the power button and the fans go but nothing else happens. Stated that the most critical power surge for a PSU comes on at the power up and if it doesn't get enough juice flowing it can't complete the process so it seems that's whats going on here. Next week I'll order a new PSU and test it out. Rig doesn't seem to need a whole lot, and this one 430w Thermaltake seems to be ideal. Just wish I had friends who had pc's and not consoles so I could borrow =/

 

[Justinus]

Watched a 20min vid on PSU diagnosing and one that tends to slip past people is my exact scenario. Where you hit the power button and the fans go but nothing else happens. Stated that the most critical power surge for a PSU comes on at the power up and if it doesn't get enough juice flowing it can't complete the process so it seems that's whats going on here. Next week I'll order a new PSU and test it out. Rig doesn't seem to need a whole lot, and this one 430w Thermaltake seems to be ideal. Just wish I had friends who had pc's and not consoles so I could borrow =/

I'm going to throw in another possibility - the only time in my life I had a CPU die on me, it exhibited the same symptoms. 9/10 (or more) attempts to post would just hang, sometimes it would end up posting and the system worked perfectly during the session. I tried everything including another PSU, different ram, and buying a new motherboard but in the end I isolated it to the CPU and RMA'd it to Intel. The replacement worked perfectly with all the same components ever since.

I know dead/faulty CPUs are rare but your symptoms really resonate with me and I spent months trying to figure that one out.

There was no explanation for why my CPU suddenly went, either.