Viruses are what people often like to blame (wrongly) for computer problems. Computer viruses work much the same way as normal ones. They ‘infect’ a computer by getting their files on its hard disk. They then begin to copy themselves all over the computer and onto anything that might carry them to another computer, such as floppy disks and emails (more on emails when we talk about the Internet). They also do damage while they are on the computer. Many viruses do annoying things, like playing a song or slowing the computer down, however some of them delete files and erase crucial data. Therefore many people get Virus Scanners. There are some major benefits to scanners. The biggest one being that they will destroy many (and maybe all) of the viruses on your computer. Their disadvantages are that they must be updated regularly, and they slow your computer down. They also give a false sense of security, making you think you are well protected when they may have missed something.

Crackers are people who break into computers. Sometimes they do it for fun, sometimes for profit, sometimes to show off. They often touch nothing. Sometimes they will take data or erase it. They tend to prefer government or corporate targets and seldom do serious hackers target normal people. However, to protect against the theft of data, many people run firewalls. Firewalls are pieces of software that identify hacker-like things and cut them off, providing a huge measure of protection for the home user. A similar term, hacker, is often used to refer to crackers, however the term hacker more properly refers to someone who knows how to exploit a computer system for beneficial purposes.