A mistake was made

Are you serious? Consoles are custom designed with proprietary designed internal hardware (motherboard, memory, CPU/APU). Even if it were possible, you'd never be able to find components that would fit inside of it, let alone work with the operating system and games since they are custom programmed for the specific console's hardware.

The XB360 is an 11-year old console. They are cheap now on the used market, in the US selling for about $75 even for the newer Slim version. Just get another one.