|What is a Virus?
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There are many different types of viruses.
- Boot Virus - affects the boot sector of a floppy or
hard disk (hard drive). The boot sector is a crucial part of
the system since it holds information about how a computer boots
(is started) up. A boot virus does not infect files, it infects
the disks on which they reside.
- Macro Virus - enter a system by exploiting vulnerabilities
in macros. Microsoft Word (.doc file extension), Excel spreadsheets
(.xls file extension) and many more...
- Polymorphic Virus - changes itself (actually, encrypts,
or encodes itself) so as to be hidden from scans. When it is
going to deliver it's damage it decrypts, does what it is designed
to do and goes back into hiding.
- Resident Virus - hides in RAM memory, from where it
can control all operations of the system.
- Trojan Horse - is a master of deception. It usually
hides in software that appears to be a legitimate application.
Once opened by the user a Trojan can do anything from delete
files, and destroying system information to less malicious things
as making your cd rom open and close and changing your desktop
icons around. Trojans are famous for creating a backdoor in
the infected computer. This backdoor allows users remote access
which can be used to control the computer for whatever use the
controller wishes. Trojans do not reproduce by infecting other
files, which is one of the major differences between a trojan
and a worm. One of the 'newer' types of Trojans include ransomware - read about it here what is ransomware?
- Worms - are a sub-class of viruses. They spread from
computer to computer and have the ability to move from computer
to computer across networks without the help of a human. A worm
exploites vulnerabilities in software and operating systems
using existing files and transport systems already in place
on the infected machine. One of the most dangerous thing about
worms is their ability to replicate. An infected system could
be used to not only send one copy of the worm out onto the Internet
but possibly thousands of copies. In the meantime, draining
the infected computer of valuable system resources.
How do I know if my computer is infected? What are the signs of a virus?
Sometimes you can't even tell you have a virus! That's part of the problem. But other signs include the following:
- system reboots? - Does your system spontaneously restart? This could be a virus or, if could be a legitimate problem with other hardware or software. That is one of the tricks of viruses. Sometimes they mimic 'normal' system problems therefore leaving the user unware of the problem.
- system slowdowns? - Has your system mysterious begun to get slower and slower as time passes? You might have a virus? or maybe not? It can't hurt to check!
- computer will not boot (start)? - You might have a virus. Try starting in Safe Mode (press the F8 key when booting), if you can boot all might not be lost. There is more to it then mentioned here but, search our resources page for more help on how to repair your own computer at no-cost.
- see strange messages appearing when you turn on your computer?
- I don't mean strange system generated messages, they have their own level of strangeness, I mean something that seems out of place - something not quite right.
- files disappearing? - Was there a program, or file on your computer one day but not there the next and you are the only user? You might have a virus. Visit our computer repair tools section to download antivirus software.
How can I remove a virus from my PC?
How can I prevent viruses
from getting on my PC?