Viruses are programs that can harm computer data and performance. There are several types of viruses including time bombs, logical bombs, boot sector viruses, worms, trojan horses, macro viruses, and script viruses. Time bombs activate on a particular date while logical bombs activate based on a specific user action. Boot sector viruses infect the hard disk boot sector and may require reformatting to remove. Macro viruses infect documents and destroy hard disk data. Prevention through use of antivirus software is the best way to maintain a virus-free system.

1. Virus
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By Dhanashree Shinde

2. What is virus???
Virus is nothing but the part of
program which harms our data badly.
It comes to us through an effected
device or mostly through internet....
Viruses decrease the performance of
the computer.
Their existence can harm our
hardware part also....
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3. Types of viruses:
1. Time bomb
2. Logical bomb
3. Boot sector virus
4. Worm
5. Trojan horse
6. Macro virus
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4. TIME BOMB
A virus program which performs it’s
task on the particular date...
So called as the time bomb....
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5. Logical bomb
It performs it’s task when particular
action has occured.......otherwise it is
not harmful.
The action can be clicking on the
particular folder...
Or anything like that
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6. Worm ........................
Worm is the program which fills the
computer with self-replicating files ,
which decreases the speed of the
system & sometimes the system
crashes.
These kind of viruses are detectable
& deletable .
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7. Boot sector virus
This virus effects the boot sector i.e.
Sector 0 of the hard disk
Once this virus enters in your system
then you must have to FORMAT your
system.
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8. Macro virus
A macro virus is associated with
application software like word and
excel. When opening the infected
document, macro virus is loaded into
main memory and destroys the data
stored in hard disk
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9. Script virus
Commonly found script viruses are
written using the Visual Basic
Scripting edition (VBS) and the
JavaScript programming languages.
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10. Trojan horse
Trojan Horse is a destructive
program. It usually pretends as
computer games or application
software. If executed, computer
system will be damaged.
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11. Prevention is better than
cure....
The best way to have a virus-free
system is to use the antivirus.
Antivirus is also the program which
deletes
the virus....i.e. It deletes the part of
the virus which is malicious.
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