Why doesn't the keyboard key work?

Question

Keyboard

The "z" key broke (copied and pasted) programs see pressing but the letter is not printed ......... why and how to fix it?

Answer 1

Restarting the laptop helped.....who would have thought! Now I would like to understand why this happened.

Answer 2

What code do they see? here, check the utility .
Maybe your function turned on when the button began to work only with Fn pressed, or maybe something else. Without details - telepathy does not work.