When I touch marked switch it's working again, after few day again the same problem.

Any idea somebody?

Same issue from my side, my Dell Vostro 5415 was shutdown on November 1st 2022. And I cannot power it on anymore a day later. It was off over night and on November 2nd 2022, the Vostro 5415 is dead. No reaction from the power button, I also checked the original power supply, no issues it has an LED that is lit green.

I also tried a Power Delivery 65 Watt USB-C Charger with an USB-C cable, same issue, the Dell Vostro 5415 is dead and cannot be powered on anymore. It is under warranty.

It is very unusual to experience this, and now there are two confirmed issues of this. I wonder if there is a flaw with this type of model.

I have same problem 2-3 times, in meantime there was BIOS upgrade and after that i don't face the issue any more. So if you laptop is dead you should open it (warranty ?), connect/disconnect switch on the picture above and if succeed to power on upgrade the BIOS.