Perseverance alone does not assure success. No amount of stalking will lead to game in a field that has none.--I CHING
SOMETIMES HACKERS TARGET SPECIFIC COMPUTERS, BUT MOST OF THE TIME, THEY JUST LOOK FOR THE EASIEST COMPUTER TO BREAK IN TO. Once they break into a computer, they can use that computer to store incriminating files that they don't want found on their own computers. Other times they may use a compromised computer as a launching pad for attacking larger, more sensitive computers, such as those belonging to government agencies. That way when the government tries tracking down the hacker, the trail leads to your computer instead of the hacker's.
Of course, nobody can attack your computer if they can't find it. If you keep your computer disconnected from the phone lines and the Internet, and then lock it up so no one but you can touch it, you can be pretty sure that no one will ever be able to hack into your computer. Unfortunately, most people use their computers to connect to the Internet or a local area network, which means that every computer can be a potential target for a hacker, including every computer that you use.
When an army needs to find a target, they send out scouts who attempt to sneak across a battlefield to report back on what they find. Likewise, when a hacker wants to break into a computer, he needs to scout out possible targets to determine which ones to attack. Three common ways that hackers scan for targets include war-dialing, port scanning, and war-driving.