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First of all, what are computer viruses?
Now before you
begin, you should get some facts straight about viruses.
Firstly, they are not actually living creatures. They are
just a program like any other, except that they copy themselves
on to other programs, they 'infect' it. They cannot actually
run by themselves. To 'activate' a virus, you need to run
the program which was infected. To be classified as
a virus, a program needs to be able to copy itself to another
program ('replicate'), by executing its code. |
| This
is the best definition that I have found: A computer
virus is a self-replicating program containing code that
explicitly copies itself and that can "infect" other programs
by modifying them or their environment such that a call
to an infected program implies a call to a possibly evolved
copy of the virus. This comes from the comp.virus
FAQ , an excellent (but lengthy) piece of information
about viruses.
From all of this
information, you should be able to see, that you cannot
get infected by a computer virus, by just reading e-mail,
or opening a word document. Unfortunately, this is not entirely
true. There is a programming language, called WordBasic.
This is used to write macros for Microsoft Word. It is also
used, by some evil (and bored) people to write virii. These
would be started when a document, which is already infected
is opened. |
| I think I have a virus, what do I do?
So, you think
you have a virus? Well, maybe you don't. Many people just
think that they have a virus, because something is wrong.
The computer is slower, you can't read floppy disks any
more... These are not sure signs of infection. There could
be some hardware problem (maybe your floppy drive is getting
old), or it could be caused by a new software that you have
installed, or even a change in the configuration files.
The first step
to take to check for virus infection, is to use a reliable
virus checker. However, no matter how much they tell you
how good they are, I recommend using at least two of them.
The more famous ones are (note that these are in ALPHABETICAL
ORDER, not performance) :
Mcafee
Norton anti-virus
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| After you have installed them, run them to see if they find
a virus on your computer. Be sure to turn "heuristics" off
if you can, as this will greatly reduce the number of false
alarms. If there is only one infection, it may be a false
alarm. This simply means that the computer thinks you have
a virus when in fact you don't. If the scanner tells you it
can clean them, you should make a back up copy of all the
infected files. You can then let the anti-virus clean the
originals only (not the backups). After you have cleaned them,
try running the programs, to see if they work. If they appear
to be working well, then all is fine, and you can delete the
backups. If however they are not working, then you should
delete them, and restore your backups. You should try other
scanners, to see if they can remove it. |
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Scanners can usually
remove some viruses that others can't. If you can't find anything
that will remove it, and you have an uninfected backup, then
you should re-install it. If you haven't got any backups,
then I'm afraid you will have to wait a while for a new update
of your anti-virus scanner, so that they will be able to remove
it. During this time, you should not run the infected program
under any conditions. If the program is not important, you
can always delete it. If you do not know what the file is
used for, do not delete it! |
| After you have finished your new scan, you should do another
scan, with a different scanner. This should be done, to pick
up the viruses that might have been missed by other scanners.
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How do I prevent a virus infection?
Well the simplest
solution is to always leave your computer turned off, but
that might not be too useful (and then there is no point
in owning a computer). Otherwise, be careful with any new
things that you install on your computer, that is any floppies,
and anything off the 'net.
A note on floppies, if you are just going to be reading
it, it's worth putting the lock on it, to disable writing.
If you read someone else's floppy on your computer, always
scan it.
Another thing that you should always do, is watch anybody
that uses your computer. They could bring a virus on, even
if they don't mean to! Of course that is not always possible,
so you should consider using a scanner that stays in memory.
It checks all files before you open them, and also scans
memory when you load it.
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