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EFFECTS OF VIRUS
Files become corrupted or the content of the files gets deleted.
A virus can damage or destroy the operating system.
A virus can reduce memory space.
TYPES OF COMPUTER VIRUS
There are various types of computer viruses that infect the computer in different ways. The
most commonly known categories of computer viruses are:
Program File Virus
A program file virus, also known as the file-infecting virus is a type of computer virus that
infects executable files (program files such as .exe, .com, .sys, etc. files) to make them
unusable or damage permanently. When an infected program file is executed, the code of
the virus also gets executed.
Boot Sector Virus
A Boot sector virus is one of the most hostile types of computer viruses that infect the boot
sector or the Master Boot Record (MBR) of hard disks or floppy disks. Once a computer
system is infected by a boot sector virus, any disk connected to the computer will also be
infected. The most commonly known boot sector viruses are Michelangelo and Stoned.
Macro Virus
A macro virus is a type of computer virus that is primarily designed to infect a specific type
of document such as Word or Excel files. If we open a macro virus-infected document, the
macro virus gets active in the memory and starts infecting other documents. Sometimes,
a macro virus sends itself by attaching with an e-mail to the people in the user's address
book. Melissa and Bablas are the most commonly known macro viruses.
E-mail Virus
An E-mail virus is a type of computer virus that transmits from one computer to another
through e-mail messages. Some e-mail viruses can also be transmitted as an infected
attachment with the e-mail message. It gets active in the memory when a user opens an
infected e-mail or attachment. It sounds very simple but an e-mail virus can erase files,
destroy information and cause computer crashes.
WORMS
A worm is a self-propagating program that works without human intervention. It is a kind
of malware that uses a computer network to send copies of itself to another computer on
the same network.
Computer Malware 103

