Ways That Computer Viruses Spread

For a virus or similar program to have any great impact it needs to be able to spread from one machine to another. They are specifically designed to get access to parts of your computer system that allow for communication with other machines. Below is a discussion of some of the most common methods.

Boot Infectors

Every disk (hard disk, floppy, CD, DVD) contains a boot sector whether it is a bootable disk or not. When a computer is turned on, it looks for boot informati...


For a virus or similar program to have any great impact it needs to be able to spread from one machine to another. They are specifically designed to get access to parts of your computer system that allow for communication with other machines. Below is a discussion of some of the most common methods.

Boot Infectors

Every disk (hard disk, floppy, CD, DVD) contains a boot sector whether it is a bootable disk or not. When a computer is turned on, it looks for boot information. If the computer finds a disk with boot information, it reads that information and uses it to properly start the computer. If for some reason that boot information is infected with a virus, the virus is activated and possibly transferred to the computer's hard drive (if the infection was on a CD for example).

Once the boot code on the hard drive is infected the virus will be loaded into your computer's memory every time you start your computer. From memory the boot virus can travel to any and every disk that is put into your computer. This is how the infection spreads.

Most boot viruses could be on a system for a long time without causing problems, simply existing there to spread themselves. Often such viruses are designed to activate their bad behaviour on a specific date (Halloween for example). There are some nasty boot viruses that will destroy the boot information or force a complete format of the hard drive immediately after they get into a computer.

Program Infectors

When an infected application is run the virus activates and is loaded into memory. While the virus is in memory any new program file that you run can become infected. This means that there will be increasingly more applications on your system that are infected. Multiple infections are very common and will certainly cause system problems.

Program files may function without any problems for some time but eventually they will have problems or multiple infections brings the entire computer system down. The data the program produces may be a first sign of infection such as saving files without proper names, or with incorrect/incomplete data being saved.

Viruses of this type are often designed to seek out programs that are used to share information between users/computers such as email applications, screen savers, office document Macros, and self-extracting compressed files.

Through e-mail attachments

Many of the most dangerous viruses are primarily spread through e-mail attachments - files that can be sent along with an e-mail message. In such cases, the user of an infected computer unknowingly attaches an infected file to an email message, and then sends the email to a friend or colleague. When the email is received, the virus is launched when the file attachment is opened, thus infecting a new computer. Email messages with animations, automated greeting cards, jokes, photographs, spreadsheet and document files, all have been documented to contain virus files.

More and more frequently these days mass mailing email worms/viruses are being released. These attacks AUTOMATICALLY scan your computer's files for any email address it can find and then uses your email application to AUTOMATICALLY send infected messages to any email address found in any file on your computer (not just email message files).

It is important to be aware of the emails that you open to make sure that they do not contain harmful viruses. Even emails from family and friends could have a virus, if that person's computer is infected. This is where an anti-virus software would be really helpful in detecting if there is a virus in any incoming messages.

How Viruses Contaminate Your Computer

Viruses are little bits of software that normally have a negative impact on our computers when they are activated. Usually viruses are attached onto other software programs (games, disk utilities, office documents/Macros, screen-savers), and are activated when these normally harmless programs are started.

A virus is inactive until the infected program is run or an infected boot record on a floppy/CD is read. When the virus is activated it loads into your computer's memory ...

Viruses are little bits of software that normally have a negative impact on our computers when they are activated. Usually viruses are attached onto other software programs (games, disk utilities, office documents/Macros, screen-savers), and are activated when these normally harmless programs are started.

A virus is inactive until the infected program is run or an infected boot record on a floppy/CD is read. When the virus is activated it loads into your computer's memory where it can perform its nasty job or spread itself to other programs on your system or computers in your network.

Floppy disks used in an infected system (or CD-Roms/DVDs burned on an infected system) can then carry the virus to another machine. Programs downloaded from USENET, or file-sharing programs (Kazaa, Morpheus, Limewire etc.) can also spread a virus. More frequently now, email is also becoming a favourite way to spread viruses, Trojan horses and especially internet worms.

It should be made clear, that USENET and file-sharing programs do not create viruses or infected files in any way. It is certain anti-social people who create viruses, and then use these services to spread the infected files to other users on the system.

This is very similar to cars and highways in that Ford, Toyota or the highway makers do not cause traffic accidents, it is the idiot who got drunk and then drove who causes a 14 car pileup. Of course if there weren't cars or highways there wouldn't be an accident... then again, the idiot would still be getting smashed and driving his horse-carriage into the store window.

When you get a virus on your computer, it can erase everything that you have on your hard drive. Each virus is different - some of them come up as strange messages on your screen, while others just work at eroding the files on the computer. A virus just doesn't appear in your computer - you have to put them there, usually by running program from the Internet that contain viruses. They sometimes come from attachments in emails. It is possible that an email from a friend could contain a virus if that person's computer is infected. With anti-virus software installed on your computer, this will tell you whether or not it is safe to open the email with a message such as "No virus detected in incoming mail:

When you do get a virus through programs or mail, it hides in your computer and when you save data in the computer, you also save the virus. Then it starts to infect all the other files in your computer. When you send files to a friend or co-worker, you also send the virus to his/her computer. After a while the virus starts to crowd the data in your files and causes major problems with the system, such that you may not even be able to open important documents or you may not be able to open any of the programs on the computer. The virus won't affect the memory of your computer, but it will affect any disks that you use to save your work.

How To Keep Your Computer From Spreading Viruses

There are some simple steps you must take to avoid becoming a victim of computer viruses and also stop from spreading viruses to others. Here are some things that you can and should do.
Email Issues to watch

Never open an E-mail with an attachment you were not expecting.

The latest batch of virus programs are often spread by E-mail. Even if your anti-virus program does not warn you about the attached file and even if the eMail appears to come from someone you know, do ...

There are some simple steps you must take to avoid becoming a victim of computer viruses and also stop from spreading viruses to others. Here are some things that you can and should do.
Email Issues to watch

Never open an E-mail with an attachment you were not expecting.

The latest batch of virus programs are often spread by E-mail. Even if your anti-virus program does not warn you about the attached file and even if the eMail appears to come from someone you know, do not open it if you were not expecting it, and if you were expecting it, only open it AFTER scanning it with your up-to-date virus software.

Scan ALL incoming email attachments (regardless of who sent it).

Be sure to run each attachment you plan to open through the anti-virus check. Do this even if you recognize and trust the sender; malicious code, like Trojan horses, can slip into your system by appearing to be from a friendly source.
Turn off the 'automatic preview' in your email program.

Automatically previewing an email message has the exact same effect as opening and reading an email. My of the newest internet worms, trojans, and viruses simply need to have an email message read in order for them to be activated. Turning off the preview feature allows you to scan any email BEFORE you actually read it.

Disk Issues to watch

Don't boot from a floppy disk.

Floppies are one of the most common ways viruses are transmitted. If you are using a floppy while working on your computer, remove it when you shut the machine off or the computer will automatically try to boot from the floppy, perhaps launching any viruses on the disk.

Web Based Issues

Keep your web browser set to its highest security level.

Its a pain to get the warning messages on every other web page you visit, but its the best way to protect yourself - especially if you use Microsoft Internet Explorer and Outlook.

Don't download programs from the Web.

Unreliable sources such as Internet newsgroups or Web sites that you haven't heard of may be willing providers of viruses for your computer. Avoid downloading files you can't be sure are safe. This includes freeware, screensavers, games, and any other executable program - any files with an ".exe" or ".com" extension, such as "coolgame.exe." Check to see if the site has anti-virus software running on their side. If you do have to download from the Internet, be sure to scan each program before running it. Save all downloads to one folder, then run virus checks on everything in the folder before using it. Regardless of where you download from, ALWAYS scan downloaded software.

Routine Maintenance

Make regular back ups of important data

Make it a habit to back up all of your most important files at least once a month. Store the back up discs in a safe place.

Clean any virus/worm/trojan off your computer
(Details: http://www.antivirus-report.com/trojan-horse-removal.html )

Using your antivirus software, perform a full system scan of your PC, hopefully it will detect and remove the virus. If a virus was detected, restart your computer and run the full scan again. Sometime the virus will keep reappearing, due to the evolving nature of viruses. Symantec is particularly fast at providing removal tools should you ever get a virus or worm infesting your computer.

What is a removal tool? Well simply put it is a simple software that will scan your computer for infections, and then remove them from your machine. You most often need this if your machine got infected BEFORE you installed antivirus software.

Top Considerations for PC Protection

And the final and most important two things to do to keep your computer clean and make sure it does not spread viruses to other computers...

Install a Firewall

If you use a broadband/high-speed method to access the internet, you need to get a firewall. A firewall is a program that defends your computer from hackers who attempt to gain direct access to your computer over the Internet. There is a very good firewall program called ZoneAlarm that will do the trick if you use Windows.

Install and use a high-quality anti-virus program.

This is the key to protecting your computer. Buy one of the major anti-virus programs - Norton Anti-Virus, PC-Cillin, or McAfee Anti-Virus. The primary benefit of the commercial packages is the frequency and ease of updating the virus definition files that these programs use to detect viruses. With new viruses popping up all the time, unless your protection software is kept updated, you start to become ever more vulnerable to infection.

Get immediate protection.

Configure your anti-virus software to launch automatically on start-up and run at all times. This will provide you back-up protection in case you forget to scan an attachment, or decide not to. And in case you forget to load up your anti-virus software, configuring it to start by itself will ensure you get immediate protection anyway. The top antivirus software programs all do this (but only if you have one installed on your computer). You do have current antivirus software installed right? If not, you can go to this page for more information on why you need antivirus software and how easy it is to use.

Choosing Anti-Virus Software

There are a number of companies that provide software solutions to virus, Trojan, and internet worm attacks. It can be really confusing when you compare three different software packages from five different companies trying to find the one that is right for you. With that in mind, there are several very important things that you need to consider when choosing antivirus software:

1) How often/fast are the virus definitions updated. You want the answer to be "As soon as a ne...
There are a number of companies that provide software solutions to virus, Trojan, and internet worm attacks. It can be really confusing when you compare three different software packages from five different companies trying to find the one that is right for you. With that in mind, there are several very important things that you need to consider when choosing antivirus software:

1) How often/fast are the virus definitions updated. You want the answer to be "As soon as a new threat is found".

2) Are the virus definitions updated automatically by the software? You want the answer to be "YES".

3) Can you configure the software to check for updates every time you go online? You want the answer to be "YES".

4) Is the software "smart" so that it can find viruses it doesn't even know about yet? You want the answer to be "YES".

5) Can it scan incoming and outgoing email automatically? You want the answer to be "YES".

6) Can you configure it once to perform automatic scans of your entire computer on a regular schedule? You want the answer to be "YES".

7) Does it provide a way to 'clean out' any viruses etc. that are found? You want the answer to be "YES".

8) Are upgrades to the software package performed automatically, regularly, and at no cost? You want the answer to be "YES".

There are a few major players in the field that you should know about in order to make an informed decision about which antivirus software solution to buy and use. There are Norton Antivirus, Trend Micro's PC-cillin, and McAfee Antivirus. Sophos and Grisoft’s AVG are also very god choices. All of the top antivirus solutions will provide each of the eight points above (and more).

There are quite a few smaller players on the market as well. In many cases they are quite good. However, most of the smaller players in this market don't have the resources (yet) to keep up with constantly changing virus threats. For now I would recommend staying away from them. Not because they are poor products, but simply because they aren't able to consistently provide each of the eight requirements above.

The first few days after a new virus appears are often when it can do the most damage. The sooner you get an update the better. The big 3 will provide automatic updates to new threats usually within days of a new virus being found. Sophos and AVG are similar. Smaller players may take several days to provide updates, which are often not automatic.

This should be enough basic information to help you on your way to choosing a good antivirus software. If you’d like to learn more first, there is plenty to read at http://www.antivirus-report.com/antivirus-software.html

Antivirus Software - Protecting Your Computer's Data

When you buy a new computer you must protect your investment from malicious software programs such as viruses, worms, spyware, and trojans.  These programs can cause serious damage to your computer system by erasing data or providing your sensitive data to criminals. You can help protect your personal computer by installing antivirus software to remove and prevent nasty viruses and spyware.

There are various antivirus programs available on the market and while they all do the same job, there are several things to keep in mind when choosing a program.

First you will want to consider the ease of use of the software.  The average computer user is not tech savvy so you will want your antivirus software to be very user friendly.  Look for features such as easy configuration as well as scanning your system on demand.  The software should also automatically check for updates.

A good antivirus program will also be able to remove dangerous viruses, trojans, and worms and prevent new ones from infecting your computer.  If the program cannot completely remove these viruses, it should at the minimum be able to keep the virus from spreading.

It is also important to ask if the software is a system hog.  Many antivirus programs can use up a lot of your computer's resources slowing down your system.  This can cause problems if you plan on running your antivirus software in the background while you continue to work.  There are many good programs available that use resources more effectively.  They run unnoticed in the background while you continue to work normally.

Some antivirus programs do include spyware prevention but in order to be fully protected, you may opt for purchasing separate spyware software as well.  A separate spyware program can help ensure that your computer is safe from spyware issues that a combo program may not be equipped to catch.