> software-defined hardware component that does the same thing
No, you cannot.
A hard-drive needs to a have a physical hysteresis. An input/output device needs to transmit power, and be powered, by an electrical field. A visual device needs to emit light on electrical stimulation, and so on.
The only sense, in the end, in which a "computer" survives its devices being changed is just observer-relative. You attribute a "3" to one state and a "1" to another, and "addition" to some process. By your attribution, does that process compute "4".
But it computes everything and computes nothing. If you plug in a speaker to VGA socket, the electrical signal causes an the air to move, sound.
The only sense in which a VGA signal is a "visual" signal is that we attach an LCD to that socket, and we interpret the light from the LCD semantically.
The world is a particular way objects in space and time move, those exhaust all physical properties. Any other properties are non-physical, which is why this kind of computationalism is really dualism.
You suppose it isnt your physical mechanism and its relationship to your environment which constitutes your thinking -- rather it's your soul. A pure abstract pattern which needs no devices with no specific properties to be realised.
Whatever this pattern is, if you played it through a speaker, it would just be vibrations in the air. Sent to an LCD, whitenoise. Only realised in your specific biology is it any kind of thinking at all.