Worm or Virus...What's the Difference?

Everyone has been infected with a virus at one time or another either through the common cold or the flu. A virus attacks the human body by entering through one of the many openings and attaching itself to a host cell. It releases a piece of genetic information into the cell and recruits the cell’s enzymes to propagate the genetic information. Once the genetic code has been adequately replicated, it destroys the cell and attacks cells nearby.

How does a computer virus simulate a biological virus? Just as a biological virus injects its own genetic information into a cell and interferes with the body’s normal operations, a computer virus is a program written to interfere with the proper functioning of a computer. It may damage programs, delete files, reformat hard disks and perform other forms of destructive acts.

To be classified as a virus, a program must meet two criteria. It must be able to execute itself by placing its own code in the execution path of another program. The program must also be able to replicate itself by replacing existing computer files with copies of the virus-infected files. Similar to the way a biological virus requires a host cell, a computer virus requires an infected host file to propagate itself.

Viruses have become the villains of the computer world, propagating themselves and destroying everything in their path. However, another tool of destruction, known as the worm, has been creeping into the computer industry. Most of us have heard of the dreaded Blaster worm that attacks Microsoft websites, but what exactly is a worm and how does it differ from a virus? Actually, a worm is a type of virus that attacks the computer in a method differing from the way a typical virus attacks a computer. Unlike the typical virus, the worm does not require a host program to propagate. A worm enters a computer through a weakness in the computer system and propagates itself using network flaws.

The typical virus requires activation through user intervention, such as double clicking or sending outgoing email. However, a worm releases a document containing the “worm” macro and sends copies of itself to other computers through network flaws, therefore bypassing any need for user intervention.

So, what can you do to protect your computer from virus infection? There are a number of preventative measures that you can take. For example, you can purchase and continually update virus scan software. Make sure that this software contains the “real-time” scanning feature which monitors all incoming and outgoing mail. You may also install a firewall which prohibits unauthorized access to your computer. By installing these preventative devices, you can proactively defend against viruses.

What Should I do if I have a Virus?

What do I do if I find out that I have a virus on my computer? Know that it’s not the end of the world. As a courtesy, contact everyone (by phone, preferably) you have been connected by email to warn them possible exposure to the virus right away.

Clean your computer with anti-virus software. If your computer is still not functioning and you have data you are concerned about recovering, consider hiring a trusted expert. Often data can be successfully extracted from an injured hard drive, but the process is complex and will involve another computer, special software, and a technician with a lot of experience in data recovery.

As a last resort, reformat your hard drive, even if it means destroying all of the information located there. Reinstall the software and data using your backup files.

Is My Computer Infected?

How can you tell if your computer has a virus? There are warning signs that your computer may be infected with a virus. For minor viruses, you may encounter strange messages, images, noises or music on your computer. An infected computer may have less memory available, or you may notice name changes. A computer infected with a virus may be missing programs, or files may malfunction. If you encounter any of these characteristics on your computer, you are most likely experiencing an attack from a virus.

Is there any hope? How can you protect your computer from viruses? If you do not have any virus software on your computer now, consider installing some soon. Be sure to update your anti-virus software regularly; this way you’ll be protected from new viruses that crop up.

Use your software to scan for viruses weekly. Don’t open emails from unknown sources, and be cautious when opening attachments—even attachments from people you trust. Hyper vigilance requires you to contact the sender and confirm the attachment before you open it, but this is too much. Just be aware. It Aunt Gertrude typically includes a newsly, well-written letter with the jokes she sends, and this attachment email from her comes with: “Open this now, baby!” alarm bells should go off. Don’t open it.

Constantly back up your data in case a virus attacks your hard drive and you need to reformat. Better yet, set up your computer to automatically back up your data weekly so that you don’t have to worry about this chore.

What Do Viruses Do?

Today’s viruses are far more potent than the beginner versions we saw several decades ago. Viruses may be sent by opening email attachments, clicking on spam, visiting corrupt websites and links online, opening spreadsheets or even the original method—infected disks. But the Internet is now the superhighway for virus transmission.

Some aggressive viruses—such as the Melissa virus—automatically duplicate copies of itself to the first 50 people in your computer email address book. A frightening prospect—opening an email from someone you trust to be greeted by a virus, and that’s exactly what the author is counting on, your trust.

The damage caused by these viruses varies from minor delays in computer function to complete destruction of your hard drive. For companies, the price is far higher. A downed website can cost a company millions of dollars a day.

How does the virus infect your computer? Because floppy use is nearly extinct and the majority of CDs that change hands cannot be altered, you will most likely bump into a virus through online activity.

Some viruses attack your boot sector, the start up section of your hard drive. Other viruses infect executable program files, activating each time the program is started. The virus travels into the memory and further copies itself.

Macro-viruses are the most common type of computer virus. This type of virus attacks data files containing macros. Macros are lists of commands or actions found under key headings. The virus resembles a macro but when the file is opened, the virus is activated.

Multi-partite viruses are a combination of the boot sector and file virus. These begin in the boot sector and affect both your boot records and program files.

Who Creates Viruses?

Where do viruses come from? Every virus is created by an author with a different motive—but all virus builders feel their actions are justified. For some, a killer virus is the ultimate technical challenge, like climbing a mountain. For others, creating viruses is a form of self-expression. Some disgruntled employees, consumers or citizens turn to virus building as revenge for perceived injustices. And though it’s a frightening thought, some viruses are built and aimed by legitimate (but disreputable) businesses to weaken competitors. Other virus authors want to make their mark in Internet history; these writers get a thrill out of seeing their virus cause damage enough to attract news headlines both online and on the evening news.

What is a Virus?

A virus is a computer program designed to enter your computer and tamper with your files without your knowledge. Once the program containing the virus is open, the activated virus can not only infect other programs and documents on your computer, it can duplicate and transmit itself to other computers that are connected to yours, just like a physical virus can move from one human host to another.

Viruses began in the late 1980s as personal computers and electronic bulletin boards became more common. Back then, operating systems, word processing programs and other programs were stored on floppy disks. Hidden viruses were programmed onto these disks; as the disks were transferred from person to person, the virus spread.

What to Look for in Antivirus Software

All antivirus software is not created equal. Like any other category of consumer goods, it has its good, its bad and its mediocre. The choices are broad and wide. Software offerings from around the globe grace the reviews of antivirus software at TopTenReviews, but in your efforts to decide which best antivirus software to buy, remember that it really comes down to just two factors: user-friendliness and effectiveness.

Top antivirus software should be easy enough for a computer user to both install and install. The software should effectively seek out and identify virus threats, as well as clean or isolate infected files. There should be understandable reporting available for each scan and plenty of help support available, so you can be well-informed of the software’s activities and capabilities. Below are the criteria TopTenREVIEWS uses to evaluate antivirus software.

• Ease of Use – Exceptional antivirus software is simple to use, regardless of a user's computer experience or knowledge of viruses. The software should be easy to install and configure. If you need to use the interface to change settings, it should be intuitive and non-threatening to beginners. Ideally, most features will be enable/disable toggles with the power to fine-tune if desired. The best antivirus software is the kind you simply install on your system and then let it do its work.

• Effective at Identifying Viruses and Worms – The best antivirus products identify infected files quickly through realtime scanning, searching for viruses in a multitude of sources, including email, instant message applications, web browsing, etc. Scanning speed is also important. Slow antivirus software will tend to interfere with your work or gaming, and if it’s very slow or you are particularly impatient, you might have the tendency to stop or pause the scan, rendering the software useless. Generally, antivirus software scans your hard drive and files looking for known viruses.

• Effective at Cleaning or Isolating Infected Files – Truly capable antivirus software thoroughly cleans, deletes or quarantines infected files, keeping them from spreading throughout the hard drive or network. Proactive/heuristic testing enables the antivirus software to detect and quarantine code that looks and acts like a virus even before it has been reported. This could be critical in protecting you on a “Day Zero” attack and spare you from being one of the first casualties.

• Activity Reporting – Antivirus programs should give immediate notification of viruses found by realtime scanners and should provide an easy to read report of scan results, including what was found and what was done with infected files.

• Feature Set – A well-rounded feature set allows antivirus software to provide absolute protection. The best programs are those that offer a wide variety of tools, from basic realtime scanning to more advanced heuristic scanning and script blocking. When it comes to virus protection, the more options the better. Many of the best antivirus packages now include multiple protection schemes at no extra cost. These include antispyware, antimalware, rootkit detection, parental controls and email screening, as many of the new threats are not literally viruses, but rather a variety of malware.

• Ease of Installation and Setup – Antivirus programs should be a breeze to install, making it easy to go from installation to initial scan in just a couple clicks of the mouse.

• Help Documentation – High-end antivirus software comes with plenty of help, including support via email, online chat or via telephone. There should also be online resources, such as knowledge bases and FAQs available for quick and convenient help.

Why Buy Antivirus Software?

An unprotected computer is a vulnerable computer, plain and simple. Every year there are hundreds of viruses, Trojans, worms and other malwares, released into cyberspace designed to harm your computer. Most people don't realize that malware is everywhere and avoiding a malicious computer invader is very difficult. And usually, you won't even know you've become a victim.

Malware is an umbrella term for all malicious software. The most common are viruses and spyware. There are many different types of viruses floating through the Internet. Consider yourself lucky if you have never been the victim of a virus. There are a number of talented programmers out there with a lot of time on their hands writing software programs intended to harm your computer or your reputation. 

If you have ever come back to your computer and found it won't start or all your files erased and unrecoverable, you know exactly why you need to protect your computer. A typical virus will essentially wipe out the master boot record (MBR) of your computer, making it completely unusable. In some cases, the only thing left to do is to reformat your hard drive and reinstall your operating system losing all your pictures of the kids, work-related spreadsheets, email and more. The best Antivirus programs will stop viruses before they ever reach your hard drive and keep your computer safe, usually without you even noticing. 

A recent study found that more than 80% of home computers have spyware installed on them and the users don't even know it. Sypware, or sometimes called adware, is a small, seemingly innocent piece of software that embeds itself in your Internet Browswr. As you surf the internet, signing into email, social networks or bank accounts, the spyware program reports back to home base with all your personal information. Before long, your resources are drained, your computer slows down, and some stranger knows everything about you. 

Rootkits are also a type of spyware. In this case, a hacker takes control of your computer, without you knowing, and uses your hard drive and IP address to infect others. This type spyware is difficult to detect on your own, but top antivirus software will detect a dangerous download and immediately delete the file. 

Computers are expensive pieces of equipment. For the same reasons you lock your home and car (to keep others out), you need to have some type of antivirus protection on your computer. There is an arms race out there between malware producers and antivirus software producers. And it escalates daily. Remaining unprotected is a sure-fire way to become collateral damage in this war. The cost to prevent and protect yourself is much lower than the cost of replacing your computer and restoring your identity.

On this site, you'll find a side-by-side comparison of antivirus software products, Learning Center articles on computer virus topics, news stories and comprehensive antivirus software reviews that will help you make an informed decision on which antivirus program is right for you.