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. What is a computer virus?

A computer program loaded to your computer with-out your knowledge or permission and runs against your wishes. It can replicate it self. All computer viruses are manmade. Computer viruses are every where and it is named with lots of different names which scare the computer users.

There are viruses which play music, change or delete files or display messages.

It is called viruses because they got some thing in common with the biological viruses. A computer virus passes from a computer to computer like a biological virus passes from person to person.

A virus should never call harmless and left on the system, a simple virus can make a copy of it self over and over relatively easy to produce. Even such a simple virus is dangerous because it will use all the available memory and bring the system to the holt. Some viruses are doing so little damage that you are unaware that your computer has been infected.

There are different types of viruses such as:
File infectors: A block of code which attaches itself to another program and it can copy itself in to subsequent applications that you run.
Macro viruses: Marco virus spread much more than other type of viruses as people frequently share data files, it spread round the word in two hours effecting tens of millions of computer.
Worms: it has been made to copy it self from one computer to another over a network.
The latest viruses have been emails viruses.

Different way to be infected:
When you open a file or when you open email is infected with a marco virus.
When downloading files or programs from browsing the internet.
From infected email message


How does a computer get a virus?
The computer virus is the same as human virus, human virus passes from person to person and computer virus passes from computer to computer.
There are many ways to get a computer virus but the common way of getting a virus is from an email attachment and that is come from an effected file connected to an email this attachment can be word files, excel files, JPEGs, GIFs or any type of files.
You can not simply get a virus from reading emails. The virus start it is work when you open and run the attachment.
But there are some new viruses are different like (klez) because you do not have to open an email attachment to release the virus, just opening the email can release the dangerous bug.
The other ways of getting a computer virus are from a file on a floppy or zip disk or when you use an infected file in a clean computer the file infects the clean computer.
Lots of people download infected files from the internet and they start to share them with there friends, in this way the virus spread very fast to all there computers.
If you found that your computer has been infected you, should assume that every disk or computer that you work with or nearby is infected because most of the viruses are spread very fast in the computer and damage your system.
To reduce the chance of getting a virus you should be really careful with the files you take to your computer even if they are from one of your close friend because most of the time people transfer file with out being sure it is not infected.
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