Building a PC based on a Dell Dimension C521 case?

Question

Do it yourself

Good afternoon. I bought a Dell Dimension C521 computer case from my hands.
Included with the case was a cooler and a power supply.
I am interested in the following, I can finish with a file, as they say, the case itself and install a mini-itx motherboard with all the components there.
Since the complete motherboard was a BTX form factor.
But the complete power supply was originally designed for BTX and, accordingly, it does not fit into the socket of modern ATX motherboards. Are there adapters for such undertakings or is it better to buy an original board in China, the question is not about money, but the adequacy of all actions :)

Answer 1

The appropriate action would be to buy a mother.
If you want to suffer garbage then saw it under itx.
According to the connector, take a connector from any ATX power connector and transfer the pins from yours to it, you will find the pinout in the internet :)
I looked at the photo of the mother, but is there really a difference in the power connectors? I thought it was physical, but the photo is the same.