Computers are particularly vulnerable to criminal activity. At all stages (input, program, central processing unit, output, and the communication process), the computer is open to human interference from many sources. There are five general categories of computer crime: sabotage of the whole system or any of its parts, theft of services, property crimes, data crimes, and financial crimes. Detection of them is very difficult, and prosecution is even more difficult. Careful screening of employees and limited access to the computer is one way to prevent computer crimes. Another is to make detection of any interference certain and swift. More specific laws are needed in Australia to deal with computer crime. However, legal problems arise because documents such as falsified computer data can and usually are considered hearsay and thus inadmissible as evidence. Juries, because of dismissal options, are usually composed of people without the needed technical expertise to understand the nature of the crime and the legal aspects involved. Alternatives to the normal jury trials which might better be able to deal with computer crimes include pretrial conferences, trial before a single judge, trial by a panel of judges, trial by a judge and a special jury of qualified lay people having expertise in those areas likely to arise in the course of the trial, and trial by a judge sitting with assessors. Changes are necessary not only in the conduct of trials involving computer crimes, but also in the penalties which are imposed and which can act as deterrents to computer crimes.