Computer forensics deals with retrieving material from a computer, thus allowing for evidence to be used in a criminal investigation. Almost all information can be recovered from a computer’s hard drive, even information that has been deleted, unless the hard drive has also been wiped clean. However, there are certain rules and regulations to follow if information that has been retrieved from a computer is going to be used as evidence in court. It’s not simply a case of any underhand tactics can be used to prove a person’s guilt or innocence and there are only certain court approved tools and software that can be used. This article will discuss four of the most common used tools and techniques from around the world.