Hacking by definition isn't nearly what people assume when they hear the word "hacker".

A regular user (non-hacker) only knows what they need to know. A common use of a computer for a regular user is word proccessing. In that case the person would know how to start the computer, get into the word proccessor, some (maybe alot) of how to use the word proccessor and then how to get out and to shut down.

But a hacker is the person who knows much more about a computer. This person is often called the computer guru. This is the person that you turn to when your computer is beyond the point where you can get it to work properly.

In short, if you know an operating system well then you are a hacker. Its just that some hackers get into network exploration and some of those hackers use thier knowledge of the networks for criminal activities. That is what you usually read about in the newspapers.