How to prevent from hacking and getting illegal access by unknown and unauthorized party(s) to a/my computer sys

Hacking is crime and hackers use this to steal innocent people's IDs and this is "invisible threats" to the personal economy and what we can say is that they are silent killers.
How do the hackers commit crimes on net? To steal IDs, to scam people and to use this to do terror activities.
Plz see the truth here.
http://annejackson4.blogspot.jp/2013/09/hacking-it-is-crime-2-plz-help-m...