For the most part, changing a few settings, installing a personal firewall, maintaining updated antivirus software, and a little common sense will provide me with reasonable protection at a very resonable cost. Every computer connected to the Internet has a unique address. Without this address, it would be impossible for the computer to work. It's like every telephone having a unique phone number. You don't have to know the number to make a call, but without it, the phone won't work.
Hackers are just like tele-marketers.
They start with a known number, and keep adding one to it and trying this new number. Eventually, they will try all of the valid numbers and one of them is yours. How do I get this address, and what can I do to prevent the hackers from finding it. We know the hackers are scanning sequential addresses on the Internet looking for computers to break in to. If you're not there, they won't find you.