[Solved] Zalman Headphones & A4Tech Sound Card: Microphone Buzzing - Grounding or Other Issue?

Hello,
I've searched the forum and the internet for a while but couldn't find an answer to my problem.
I bought Zalman headphones with a microphone and an A4tech sound card. However, the problem is that you can't record through this microphone at all because there is a constant hum in the background. I read that maybe it's something with grounding and at first I thought so, because when I put my finger to the metal jack of the headphones or my hand on the housing, the microphone did not hum, but ... I connected my old microphone from other headphones and there is no hum here anymore and what is it like when I increase the dB eg +10 or +20.
I checked the socket is with a pin and everything is connected to the strip (I disconnected everything from it, I left the monitor and the power supply from the computer and it still hums, I connected to another strip and also the same.
I did one more test that messed with my head, namely I connected headphones with a zalman microphone to the laptop and no hum ...
The fault of the sound card is rather not, because when connected to the integrated one, it also hums, but the old set does not hum and I do not understand it.
You could say stay on the old set, but that's why I replaced it to have a little better quality and it turned out a bit poorly
My computer is on the desk with cables connected to a strip that goes to a socket with a pin.

Does anyone have an idea what else I could do?

rezu93 wrote:

I checked the socket is with a pin and everything is connected to the strip

Hello. The presence of a pin is one thing, but is it properly connected or is it hanging in the air? As it hangs in the air, it is of little use. If you touch the metal parts of the computer with your finger and the humming disappears, the computer is not grounded. If it was, your touching the housing wouldn't change anything.

I understand this logically, I have to unscrew the socket and check on the other hand if I put my hand on the computer, the electricity does not kick me and I remember that once in an old house when I had a computer connected, it was when I touched it with my hand that I got electricity.
I will check today by plugging the computer's power supply directly into the socket.

Is there a chance that it's a letter, for example, doing something like this? In general, the strip also has pins, but its cable and the side connected to the extension cord that goes to the strip also has a pin.

Added after 8 [hours] 14 [minutes]:

Ok, I checked everything in contact, there are three cables and it looks like it should be fine, but it's not ...
Out of curiosity, I checked the second contact in the same room and it's fine under it! But it's on the other side of the room and I can't connect there.
Does this mean that you need to replace the socket or try something with the cable? Maybe it's installed incorrectly.
Attached is a photo of the socket in which it works well.
The second is identical but the ground cable goes from the bottom.

Let the socket be there as it is, what matters is whether the wires in it are connected to something and whether they are connected correctly. Here, it would be most reasonable to invite an electrician who will check the effectiveness of the grounding pin, or possibly do what is necessary in accordance with the art.

If it turns out that the ground wire is not connected, you can do a possible zeroing?

Hello, the topic to be closed, the cable was not connected, so it hurt to hang, I already connected it and the humming disappeared
Thank you for your help!