PC Refuses To Turn On

[DankMemez]

My computer refuses to turn on no matter how many methods I use. I swapped power supply outlets, reset BIOS with CMOS pins, cleaned heat sink since it was filled with dust, unplugged everything and reconnected it, and any other possible method. I need some serious help right now.

Here's how it all began:
I was sitting at my desk using my desktop computer (Specs down below) while playing some multiplayer minecraft. Suddenly the server decides to automatically give me a resource pack (An in-game add on to basically change the look and texture of objects and/or entities). A second later, my PC freezes. I do Ctrl + Alt + Delete and my screen goes black. My cursor could still click the options for some odd reason. I decide to shut off my PC and turn it back. Little did I know that it wouldn't turn back on....

Currently it makes one long BEEP noise. Just an endless, countinuous beep. It only does that, however, when the PSU switch is flicked on (Kinda makes sense).

My PC specs:

Windows 10 Pro

Intel i3 2100 CPU

BIOS Version: American Megatrends Inc.

BIOS Mode: Legacy

System Manufacturer: BIOSTAR Group

Installed RAM: 8.00 GB

System Model: TH67B

My motherboard light won't turn on, and neither will the fans or the entire PC itself. Any help would be greatly appreciated. Thanks

 

[DankMemez]

UPDATE: I have tested my power supply using the green wire trick (or paperclip trick) and I've found out that it doesn't work. I grabbed a spare power supply (same exact look and model of my other one) and did the trick again. It gave one very short beep and the power supply fan started up. I decided to connect it back to my motherboard to test. Sadly it did not work. It gave the same long beep as before. Do you think it could be the 24 pins not getting power into the power supply? It seems like it's not receiving power once it's plugged into the motherboard. At least I know that the noise was not coming from the motherboard, but the power supply. Still need help and fast 🙁

 

[DankMemez]

SOLUTION: I have tested my friend's psu on my PC and it works, which means it's not the motherboard, but the psu itself. I am ordering a new one but would still like to know how this happened.