文档介绍：- 1- Computer virus Abstract: puter virus puter program that can copy itself and infect puter. The term "virus" is monly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability. A true virus can spread from puter to another (in some form of executable code) when its host is taken to the puter; for instance because a user sent it over work or the , or carried it ona removable medium such asa floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to puters by infecting files work file system ora file system that is accessed by puter. As stated above, the term "computer virus" is sometimes used asa catch-all phrase to include all types of malware, even those that do not have the reproductive ability. Malware puter viruses, computer worms, Trojan horses, most rootkits, spyware, dishonest adware and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to puters works, while a Trojan horse isa program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm puter system's data or performance. Some viruses and other malware have symptoms n