Here are some of the nasty bugs that can infect your computer, courtesy of commercial or hacker sources:
Viruses: Bits of software that infect other programs and rely on them to reproduce themselves. Sometimes considered along with worms as part of a single category known as "malware."
Worms: Like viruses, but more complicated. They make copies of themselves independently of other software.
Trojan horses: Software inserted into your hard drive to let others access or hijack your computer to get information or send spam.
Adware: Spy programs that send information to others about you and what you are doing. When you download free software on Kazaa, for example, you may be accepting these into your computer by clicking the "I agree" button. A scan of this writer's one-year-old laptop revealed infection by 199 adware programs, enough to seriously slow the computer.
Spyware: A more malicious data miner aimed at stealing confidential information like passwords and account numbers.
Network viruses: Malware coming over a network directly into your memory without first lodging on the hard drive. Can arrive as a series of small bits of information that are individually harmless, until they team up on your computer.
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