The impossible problem of no display and no usb power. Try me, I tested everything.... help!!!

1. I got a gaming desktop computer here that has no video signal sent to the monitor and no USB power.
The PC start and light up
2. All the fans (CPU, GPU, case) turn on and the LED (motherboard and fan) too
3. I change the motherboard and PSU to brand new ones and got nothing. They are still in the computer, and the old motherboard is in my second desktop PC, working great
4. I swap the GPU with my other one: no result, but the GPU of the PC having a problem worked great in my second PC.
5. I tried the CMOS technic, no result.
6. Tried changing the ram, reseating it, and starting without it; nothing AND the RAM work great in my second pc
7. I swap the CPU with one I have in my second PC; still nothing
8. Tried starting without SSD and HDD; nothing
9. Tried numbers 5, 6, 8 at the same time; still nothing
10. Tried changing the HDMI cable, no result.
11. DP cable also isn't working, and changing monitor isn't working either.
12. Having two monitors at the same time isn't working either
13. Before all those, I sent the PC to a PC shop and they found nothing. They gave me feedback on what they tried and had said it was either the motherboard or the CPU.
14. When plugging HDMI or DP cable, the monitor get out of sleep but still found no signal
Guess they were wrong and I lost 126$ with them, kinda sad
My brother whose pc is to tell me it had started having problems after 3 consecutive power outages and it was the other morning that the no display happen.
But hey, he like lying so it could also be something else, he also told me windows started having problems first.
His pc had work for 7 months until he now got a problem.

Do y'all have any other ideas??? 🤔

Setup
PSU: 750W 80 plus - corsair
Motherboard: ASUS ROG b550-F
SSD: M.2 NVMe 1.4 Samsung 980 250Go
HDD: Seagate 1To
RAM: Corsair Vengeance LPX 16Go DDR4 3600
Case: NZXT H710i White
Thermal paste: Graphite Pad by Innovation Cooling (before you say its the problem, know that my second PC work with this pad and has great temperature with an AMD ryzen 5 )
CPU: AMD Ryzen 7 3800X 8cores
CPU cooler: AMD's CPU included fan -> LED Wraith Prism
GPU: ZOTAC RTX 3060 OC 12Go GDDR6

good thing is I got a buzzer like this one except it’s doesn’t have the plastic header, but all try making a diy solution.
I don’t know what reinstalling windows could do because it’s installed on the SSD, and even without storage, the computer should still boot on the bios right?
Ima also gonna try building it out of the case to see if the case can be the problem.

Thanks for the tips, all be back to give news

Quick Update ---------------
1. I tried the speaker before rebuilding the PC, and I don't get any sound. I tried connecting it in different ways (5v / gnd, 5v / speaker, speaker as VCC / gnd (tried both))
I don't get any sound. Would that mean it doesn't even boot in bios? (See picture attached to see pin diagram)

2. I found out by reading that one of the Q-LED, the DRAM, is on and stays on.
It is said it's due to a problem but I'm not quite sure what it is

Ima start disassembling

EDIT: I got the same motherboard and RAM on my second PC, and the Q-LED form DRAM isn't on

I’m done building it out of the case.
There is now only the power switch of the case that is connected to the motherboard, because of multiple try and fail, I now only have the essential thing connected
1. My second you, so now I know it’s not the problem for sure
2. The mother is new, and I got the old one which the problem had start with in my computer, I know it ain’t the peoblem
It self but maybe it contain the problem (memory?, dram?? (What is this)?, cmos?)
3. Got the ram etc etc

The problem still persists

After testing, without any memory, the system does send beeps.
But I’m not quite sure if it’s 1long - 2short. Or 3short
I think it’s more of a 1long / 2short but there isn’t a big diff between short and long if it’s the case

I’m also gonna try putting my storage of the my good pc on this bad one and see

Btw Peter, thanks for the answer but 3200Mhz it’s the officials max compatible ram speed for the cpu, but it is possible for it to take more (to a certain point) speed. 3600Mhz work just fine on my pc with a Ryzen 5 3600x, it’s just that over 3200Mhz, if I’m not wrong it will be considered like OC, but yea, my pc is working since January 2020 and still going strong 💪

Correct me if I’m wrong, I ain’t no genius and I’m always learning!
Be back with storage test result soon

Putting my ssd in his bad pc didnt do anything, but now my pc is slower.. kinda weird

a restart make it algood again

Ok, seem like i didnt express myself clear ahah

The pc is still not working with display
My SSD in HIS bad PC didn't work

My PC was slower when I put back My SSD, but it not run normal again after a restart

The problem is still there

Okay but how am i supposed to make it work on the bad PC without display and access to USB?
I can do it on mine tho (the good one)?

Sooo, i just take a quick look of the snapshot that Speccy took.
I found quite a lot of info that I'm not sure if it would be quite right to be publish on ethernet.
Either way, if something is really important tell me and all give you the info of the snapshot

Bad pc
PSU: 750W 80 plus - corsair
Motherboard: ASUS ROG b550-F
SSD: M.2 NVMe 1.4 Samsung 980 250Go
HDD: Seagate 1To
RAM: Corsair Vengeance LPX 16Go DDR4 3600
Case: NZXT H710i White
Thermal paste: Graphite Pad by Innovation Cooling
CPU: AMD Ryzen 7 3800X 8cores
CPU cooler: AMD's CPU included fan -> LED Wraith Prism
GPU: ZOTAC RTX 3060 OC 12Go GDDR6
(Same as the first post)

My good pc
PSU: EVGA supernova 500W 80 plus gold
Motherboard: ASUS ROG b550-F
SSD: M.2 NVMe 1.4 Samsung 980 500Go
HDD: Seagate 500Gb
RAM: Corsair Vengeance LPX 16Go DDR4 3600
Case: Corsair SPEC-05
Thermal paste: Graphite Pad by Innovation Cooling
CPU: AMD Ryzen 5 3600X 8cores
CPU cooler: AMD's CPU included fan
GPU: ASUS GeForce GTX 1660 Super OC 6Go EVO

Hey Peter, thanks for the tips.
Unfortunatly i tried playing with the RAM multiple time and even only on RAM in "B1"
It hasn't work...