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3.13. PROTECTING COMPUTER AGAINST VIRUSES
VIRUS is an acronym for Vital Information Resource Under Seize.
Computer virus is a malicious code that attaches itself to a file and enters your computer system and makes copies
of itself and carries out the harmful tasks in such a way that it damages the important files of an operating system
or application programs or important data files due to which the computer may stop working.
There are various types of virus. Some of them are:
• Program File Virus: A program file virus, also known as 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.
• Boot Sector Virus: Boot sector virus is one of the most hostile types of computer viruses that infects the boot
sector or the Master Boot Record (MBR) of hard disks or floppy disks.
• Macro Virus: A macro virus is a type of computer virus that is primarily designed to infect a specific type of
documents such as Word or Excel files.
• E-mail Virus: E-mail virus is a type of computer virus that transmit from one computer to other through e-mail
messages.
Some of the viruses are designed to get activated at a certain date and time. No matter how advanced an anti-virus
software program you have installed in your computer the new malicious code will still find its way through your
computer defence system. They gain access to your computer through:
Infected files
• Infected pen drives, CD/DVD-ROMs
• Through infected file attachment of emails
• Insecure websites
• Online games
You will come to know about the virus that infected your computer through the following common symptoms:
• Computer runs very slow as it loses its processing speed.
• There will be a change in the system file size.
• An unusual increase in number of files.
• Computer restarts on its own in between.
• Disk drives or disks become inaccessible.
• An application or applications are not working correctly.
• The computer locks up frequently or stops responding.
• Dialogue boxes and menus sometimes appear to be distorted.
• An anti-virus program will either be disabled or does not run properly.
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