I mindlessly updated the Arduino board (forgetting that newer isn't always better) and now the code [That I didn't write myself] within the Processing (Java) program isn't capturing a signal.
I'm not getting any error messages either. The only thing that has changed is the lack of Signal Capture after the update.
The old computer had Arduino Software v1.8.16
No idea what the Arduino Board itself had prior
and Processing v3.5.4
My new computer has the latest versions of all of them.
Nevertheless, I don't get any signal from either the new or old now since the firmware (or library? update)