How To Protect Your Computer From Viruses

Don't risk infecting your computer with viruses, worms, or Trojans. Here's how to protect yourself.

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You've got the chills, your stomach is rolling, your throat is sore and now your fever is soaring. Yep, you caught a virus, and if you're not very careful, you'll spread it to everyone you see. Who's responsible for you feeling so lousy? Just about anyone with whom you might have crossed paths.

We all have battled such nasty flu bugs, but our computers have it even worse: they are susceptible to viruses year-round. There is a reason tech-types named those nasty bits of code that wreak havoc on your computer "viruses." After all, like the dreaded biological viruses, they are highly contagious, hard to get rid of, and often find their way into systems through otherwise innocent means.

Fortunately, preventing or getting rid of computer viruses is usually quicker than recovering from the chills-and-fever rollercoaster, and can be usually accomplished by simply remaining vigilant. However, internet security is becoming increasingly complex, (even to the point now that there are now specific courses in what is called information assurance training) and one often needs to take proactive steps to ensure maximum protection from computer viruses and prevent your computer from becoming a zombie computer.

Keep your antivirus software updated

We've all seen the headlines warning of the dangers of famous viruses: Melissa, Klez, the Sobig worm, Love Bug, and more recently, Conficker and Stuxnet. We know we're supposed to watch out for them and take steps to prevent them, but what exactly are they?

By definition, a virus is a bit of computer code that is designed to self-replicate or make copies of itself. When you run a program that's been infected or start up an infected computer, the virus "comes alive" and attaches itself to other files, causing all kinds of damage along the way.

Viruses have friends (or subcategories) called worms and Trojan horses

Unlike viruses, which spread from file to file, worms spread from computer to computer through the Internet, often by sending themselves to everyone in your address book. Passive worms need some action from you to get to work, such as opening an e-mail attachment. Active worms take advantage of vulnerabilities in a system to run on their own. Simply opening an e-mail or previewing it can launch these aggressive bugs.

Yet another form of virus, a Trojan horse, gives the appearance of being an innocent game or screen saver but can destroy files or let hackers in the back door. While a Trojan horse doesn't automatically spread, it still can cause significant damage.

Trojan horses are often used to steal personal information. Some of these viruses can lift passwords and user names by installing a keylogger while you're busy with the "fake" program it traveled in under. A keylogger can record your keystrokes and send this information elsewhere.

New strains of computer viruses

The latest twists on viruses are sophisticated blended threats, which use malicious code and computer hacking skills to do their damage. With this increasing threat, and with viruses spreading to other platforms, like mobile devices, phones, PDAs, and instant messaging, antivirus vendors can relax, knowing their jobs are secure.

There are even virus hoaxes, which are those unsubstantiated e-mails that get forwarded rapidly around the world, causing needless worry. This technological game can create even more trouble if the hoax encourages taking action, such as removing essential programs from your system.

All types of viruses have what's known as a payload, the destructive code that shows up to let you know there's trouble in computing paradise. If you've ever had a screensaver pop up that you didn't want or need, had music play unexpectedly, or have been blasted with an obscene message or image as you're working on your annual holiday letter, you've probably been hit with a virus.

While these scenes might seem like mere annoyances, or make you feel like the victim of a practical joker with a sick sense of humor, there is usually more to a virus than meets the eye. Often, they can wipe out all the information on your hard drive, cripple your operating system, delete files, or change stored information.

A common misperception of the damage that can be done with a virus is that it will corrupt your files. "Virus can corrupt your files, but it is more often that it corrupts Windows operating system files, " said Loes, of the Geek Squad. "If you cannot load Windows, you will not be able to access your files."

How to prevent computer viruses

The best way to prevent virus proliferation is to stop using e-mail. However, most computer users would agree that such a remedy is a bit drastic. Fortunately, you don't need to break your daily e-mail habits, if you take a few other, more reasonable preventative steps.

Security consultants stress the importance of keeping your antivirus software updated. The latest versions of Symantec's Norton AntiVirus and McAfee's Virus Scan both offer automatic updating. However good these are, remember they are retroactive and only act on known viruses. Just recently Microsoft has reported a new virus where Microsoft Word attachments can be compromised. Take nothing for granted!

Not so long ago, the major virus prevention advice was to not open e-mail attachments from strangers. Now, as viruses have gotten much smarter about how they spread, even e-mails from your best friend or colleague are suspect. Protect yourself by taking some of the following measures when you're working online:

Buy, install and update reputable antivirus software.
Never trust an executable file delivered by e-mail or downloaded from the Internet.
Do not open any files attached to an e-mail if the subject line is questionable or unexpected.
Always virus-scan an executable file before running it - even if you received it from someone you know.
Know the purpose of any attachment.
Back up your files regularly. If a virus destroys your files you'll be able to replace them with a backup copy.
When in doubt, always err on the side of caution and do not open, download, or execute any files or e-mail attachments.
At least once a month, visit the website for any software you use to download security patches.
Trojan horses usually are hidden in executable files with extensions such as .BAT, .EXE, .PIF, .COM, and .VBS. Be careful downloading any of these.

However you choose to protect yourself, do it today. Too many people purchase antivirus software after they've been hit. And, that's like getting a flu shot after you've spent a few days feeling miserable.