A computer virus is a computer program that can copy itself and infect
a computer without permission or knowledge of the user
Here is the List of virus:
Resident Viruses
This type of virus hides permanently in the RAM memory. From here it
can control and intercept all of the operations carried out by the
system: corrupting files and programs that are opened, closed, copied,
renamed etc.
Examples include: Randex, CMJ, Meve, MrKlunky.
Overwrite Virus
This type of virus is characterized by the fact that it deletes the
information contained in the files that it infects, rendering them
partially or totally useless once they have been infected.
Infected files do not change size, unless the virus occupies more
space than the original file, because instead of hiding within a file,
the virus replaces the files content.
Some examples of overwrite viruses include: Way, Trj.Reboot,
Trivial.88.D.
Macro Virus
Macro viruses infect files that are created using certain applications
or programs that contain macros. These include Word documents (DOC
extensions), Excel spreadsheets (XLS extensions), PowerPoint
presentations (PPS extensions), Access databases (MDB extensions),
Corel Draw etc.
A macro is a small program that a user can associate to a file created
using certain applications. These mini-programs make it possible to
automate series of operations so that they are performed as a single
action, thereby saving the user from having to carry them out one by
one.
Some examples of macro viruses: Relax, Melissa.A, Bablas, O97M/Y2K.
Encrypted
Encryption is a technique used by viruses so that they cannot be
detected by antivirus programs.
The virus encodes or encrypts itself so as to be hidden from scans,
before performing its task it will decrypt itself. Once it has
unleashed its payload the virus will then go back into hiding.
Examples of encrypted viruses include: Elvira, Trile.
Companion Viruses
Companion viruses can be considered file infector viruses like
resident or direct action types. They are known as companion viruses
because once they get into the system they "accompany" the other files
that already exist. In other words, in order to carry out their
infection routines, companion viruses can wait in memory until a
program is run (resident viruses) or act immediately by making copies
of themselves (direct action viruses).
Some examples include: Stator, Asimov.1539, Terrax.1069.
Worms
A worm is a program very similar to a virus; it has the ability to
self-replicate, and can lead to negative effects on your system and
most importantly they are detected and eliminated by antiviruses.
However, worms are not strictly viruses, as they do not need to infect
other files in order to reproduce.
Worms can exist without damaging files, and can reproduce at rapid
speeds, saturating networks and causing them to collapse.
Some examples of worms include: PSWBugbear.B, Lovgate.F, Trile.C,
Sobig.D, Mapson.
Trojans or Trojan Horses
Another unsavory breed of malicious code are Trojans or Trojan horses,
which unlike viruses do not reproduce by infecting other files, nor do
they self-replicate like worms.
Trojans work in a similar way to their mythological namesake, the
famous wooden horse that hid Greek soldiers so that they could enter
the city of Troy undetected.
They appear to be harmless programs that enter a computer through any
channel. When that program is executed (they have names or
characteristics which trick the user into doing so), they install
other programs on the computer that can be harmful.
Some examples of Trojans are: IRC.Sx2, Trifor.(source:virus portal)
E-mail viruses -
An e-mail virus travels as an attachment to e-mail messages, and
usually replicates itself by automatically mailing itself to dozens of
people in the victim's e-mail address book. Some e-mail viruses don't
even require a double-click -- they launch when you view the infected
message in the preview pane of your e-mail software [source: Johnson].
Friday, June 6, 2008
Speed Ur Pc
All Windows computers slow down over time – this is simply a fact of life, but that
doesn’t mean that you have to live with it. Contrary to what the computer industry as a
whole would have you believe, you do not have to upgrade your hardware every few
months to keep your computer fast and responsive to your requests – you just need to
clean up after it once in a while.
It is HIGHLY recommended that you create a backup of your computer before
undertaking any of these steps. This will help insure that you can go back to a previous
working version of your system if you make a mistake. The easiest way to do this is to
create a system restore point. For instructions on doing this, press F1 on your computer
and search for “Create Restore Point.
1.Remove Unused Applications
1) Click Start, click on “Control Panel” in the Start Menu.
2) Double-Click on “Add or Remove Programs” in the window that opens.
4) Scroll through the list of programs, look for anything that you do not recognize or
that you have not used in a while and don’t need.
5) Click on the name of a program that you would like to remove; it will expand and
show more details about the application.
6) On the right side of the highlighted application, there is a button labeled
“Remove”, click it.
7) You will be asked to confirm that you would like to remove the selected
application. Click on the ‘OK’ or ‘Yes’ button.
8) Each application is different, so you may be presented with an uninstall wizard. If
this happens, follow the directions on the wizard and you should be through in no
time.
9) Once the application has been removed, you may be prompted to restart your
computer. Click ‘NO’ or ‘Restart Later’ – you want to keep uninstalling
programs until you are down to the applications that you use on a regular basis.
10)You should be presented with the list of installed applications again, but with the
application you previously selected removed from the list. You can now repeat
steps 4 through 9 until you have removed all the applications you no longer need.
2.Defragment Your Hard Drive
3.Run The Hard Drive Cleanup Utility
1) Click Start, All Programs, Accessories, System Tools, then Disk Cleanup.
2) You will be asked to select which drive you want to cleanup, choose your primary
drive and click OK.
3) You will now see a progress bar on your screen – the tool is trying to determine
how much space it can free from your hard drive. After a few minutes it will
offer you a list of types of files that you will be able to remove from your
computer, and how much space can be gained by removing them.
Select which files you would like to remove – but be careful, you may actually
need something. Your best bets are usually anything that has the words
“Temporary Files” in it.
5) When you are ready to delete the selected files, click ‘OK’
6) Once again, walk away and let the system run. With this tool, it is recommended
that you let it run overnight.
4.Download and Run a Registry Cleanup Tool
A registry cleanup tool is a program that runs through your registry (a fancy name for a
configuration file) looking for errors and correcting them. There are several very good
ones on the market that offer you a trial, but some of them do require you to purchase the
entire package before getting full functionality. We have found no free tools that perform
a decent job of cleaning your registry, but there are a couple of full features trials that will
work nicely the first time, which is generally all you need.
Please leave ur comment to improve this blog
refrence taken up from book by Christopher Shireman
doesn’t mean that you have to live with it. Contrary to what the computer industry as a
whole would have you believe, you do not have to upgrade your hardware every few
months to keep your computer fast and responsive to your requests – you just need to
clean up after it once in a while.
It is HIGHLY recommended that you create a backup of your computer before
undertaking any of these steps. This will help insure that you can go back to a previous
working version of your system if you make a mistake. The easiest way to do this is to
create a system restore point. For instructions on doing this, press F1 on your computer
and search for “Create Restore Point.
1.Remove Unused Applications
1) Click Start, click on “Control Panel” in the Start Menu.
2) Double-Click on “Add or Remove Programs” in the window that opens.
4) Scroll through the list of programs, look for anything that you do not recognize or
that you have not used in a while and don’t need.
5) Click on the name of a program that you would like to remove; it will expand and
show more details about the application.
6) On the right side of the highlighted application, there is a button labeled
“Remove”, click it.
7) You will be asked to confirm that you would like to remove the selected
application. Click on the ‘OK’ or ‘Yes’ button.
8) Each application is different, so you may be presented with an uninstall wizard. If
this happens, follow the directions on the wizard and you should be through in no
time.
9) Once the application has been removed, you may be prompted to restart your
computer. Click ‘NO’ or ‘Restart Later’ – you want to keep uninstalling
programs until you are down to the applications that you use on a regular basis.
10)You should be presented with the list of installed applications again, but with the
application you previously selected removed from the list. You can now repeat
steps 4 through 9 until you have removed all the applications you no longer need.
2.Defragment Your Hard Drive
3.Run The Hard Drive Cleanup Utility
1) Click Start, All Programs, Accessories, System Tools, then Disk Cleanup.
2) You will be asked to select which drive you want to cleanup, choose your primary
drive and click OK.
3) You will now see a progress bar on your screen – the tool is trying to determine
how much space it can free from your hard drive. After a few minutes it will
offer you a list of types of files that you will be able to remove from your
computer, and how much space can be gained by removing them.
Select which files you would like to remove – but be careful, you may actually
need something. Your best bets are usually anything that has the words
“Temporary Files” in it.
5) When you are ready to delete the selected files, click ‘OK’
6) Once again, walk away and let the system run. With this tool, it is recommended
that you let it run overnight.
4.Download and Run a Registry Cleanup Tool
A registry cleanup tool is a program that runs through your registry (a fancy name for a
configuration file) looking for errors and correcting them. There are several very good
ones on the market that offer you a trial, but some of them do require you to purchase the
entire package before getting full functionality. We have found no free tools that perform
a decent job of cleaning your registry, but there are a couple of full features trials that will
work nicely the first time, which is generally all you need.
Please leave ur comment to improve this blog
refrence taken up from book by Christopher Shireman
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