No power at all (possible PSU or short somewhere)

[CybernatonEvolution]

Edit: I decided to buy a PSU tester and decide if it is the motherboard or the PSU that is dead. I will stick with my 970m for now; at least I will hook it to a 144hz monitor LOL. What an amazing start for the summer break; first my cloud II headset, and the now the whole thing.



I just cleaned my GPU and replaced its thermal paste. I fiddled around with the PSU connections and tried to switch it downwards (fan facing down). I reconnected everything and it doesn't turn on at all; no sign of power. I only messed around with the PSU (I was actually shaking it because I thought a screw got inside), and some stupid screw got lost in the case (found it). I had incidents of me messing around with parts/cleaning and having power cutoff, but this time there is no power at all, and the PSU is been weird lately; it is making weird sounds when I turn it off as if I will get an electric shock when I touch it.

The only time it powers only somehow is when only connect the ATX 24 pin from the motherboard to the PSU but ONLY the larger part of 24 pin's other end (the other end has two large parts instead of a 24 pin one). What happens is loud clicking, fans running and the LEDs of the case are flashing.

When I connect everything, there is no power at all. I tried the paper clipper test via Corsair's guide, but it says I need a fan (and a molex fan converter).

Should I take everything apart and try again? Is there anything I can do to isolate the problem?

 

[CybernatonEvolution]

An important update:

I tested the voltage output of the PSU with a multimeter; I put the thing on via connecting ground pin+psu on pin and I heard the usual click sound that the PSU makes when it is on.

All voltages were doubled. The orange 3.3V pins were 6.5V or something, and the 12V were 24V. I imported everything ('Murican equipment), so I use a power adapter that has a transformer/converter that supports 120V devices (220V were I live). The power adapter works fine; my monitor and my laptop are working properly.

Is the PSU transformer/converter not working or what could it be? Should I get a new PSU? Note that the Motherboard doesn't turn on at all.