How to Stay Safe Online

Nobody wants their computer to get infected with a virus. Learn how to protect your devices from malware.

When you’re online, you can be vulnerable to malicious viruses and other types of malware.

Malware can range from a mere annoyance to completely disabling your PC, and some malware scripts have even become portals for more sinister activity like hacking into sites, mounting denial of services (DDoS), or stealing confidential and personal data for fraudulent financial gain at your expense.

But are viruses serious enough to cause substantial losses? 

If you use a computer at home, you might just need to reinstall your operating system (OS) after a virus or malware infection. This isn't a very expensive task, though you might lose a day or two while you reinstall your programs and rebuild files. 

But malware that targets businesses or even your personal data could cause significant financial harm, so it's always worth protecting yourself online.

What can I do to protect myself from computer viruses and Trojans?

These days, practically everyone's online, downloading and exchanging files, and developers are in such a hurry to get their Web sites up or their files out that checking for a nasty bug is more of a courtesy than a requirement. If you're not careful, your computer can end up with a nasty virus that makes your files act oddly, crashes your computer, pops up bizarre messages, or worst of all, destroys your operating system.

A computer virus is the most subtle of computer problems. It usually loads itself into your computer system when you run a program to which it has attached itself. From the computer system, it'll then reproduce itself, much like a biological virus would, by attaching copies of itself to other programs on your hard drive. What it does then depends on the malevolence of its creator. Some viruses are nothing more than a practical joke.

They may bring up a message like "Merry Xmas" or melt your display. Most of them though, either start destroying your system or your files immediately or on a date specified by their creators—like the much-publicized Michelangelo virus, which erases important pieces of your system on March 6. "Trojan horse" programs are similar to viruses in their effect on your system, but they can't reproduce themselves.

They're usually a program disguised as something you might want to download onto your computer—for instance, a rogue, modified version of PKWare's PKZIP utility. But when you run the new program you just found, it can do anything from popping up a message to erasing your hard disk, as the rogue PKZIP utility really did.

In either case, you have to actually launch the infected program or the trojan horse for it to infiltrate your system. Though hoax e-mails, like the one about the "Good Times" virus try to make you believe otherwise, neither a virus nor a trojan horse program can do anything if you simply leave the malevolent file sitting on your hard drive.

Finding out that you copied a trojan horse onto your computer is remarkably easy. You launch the program, and the next thing you know, something completely unexpected happens—maybe your system is gone or your computer is laughing maniacally at you. But unless you notice your computer acting oddly before the virus has done its worst damage, you may very well not know you have it until it's too late.

How to avoid computer viruses

There are a few basic rules that computer users should follow to short-circuit viruses. The best-known bit of advice is this: Never open any attachment unless you know who it's from and why they are sending it. Refusing to open unsolicited e-mail of any kind is the only sure-fire way to sidestep all forms of trouble.

Antivirus software is crucial to preventing virus attacks, but this strategy only works if users update their software. Unfortunately, 'keeping it current' means updating it weekly, at least but most products today allow one to automate this process, but file downloads can be large and slow.

Factors to consider when buying an anti-virus package include cost, quality of tech support, how frequently the package self-updates and the platforms supported by the program.

Common sense is another good weapon in the fight against viruses. Be wary of opening any email attachments, even from your friends, especially if it has been forwarded to them. Set up your anti-virus product so that it automatically scans incoming e-mail and avoid e-mail software that allows automatic launching of attachments.

If all of this sounds like a lot of work, it is. There is always a tradeoff between ease of use and security but the extra time you spend updating your anti-virus software now will save you hours of time and buckets of frustration later. If you don't keep it updated, you might as well be completely unprotected.

11 simple tips to protect your computer from viruses

  1. Be sure to do a full backup of your system on a regular basis. The best way to clean up an infected file is to replace it with an original non-infected file. Not to mention the grief a current backup will save if a virus takes your system completely down. It's also a good idea to keep more than one set of backups in case the current one is infected before the virus is detected.
  2. Always use an antivirus software program, one with both an on-demand and an on-access scanner. You'll want to look for one that has a fairly complete database of viruses and that is updateable. New viruses are produced daily, so it's important to have software that can detect the latest threat.
  3. Be sure to read the manual and follow the directions of the software program to ensure it's protecting you properly. Also, consider buying and using two different brands to be doubly protected. See our review of anti-virus programs.
  4. Update the virus database in your anti-virus program regularly (each month or by the direction of the manufacturer).
  5. On a PC, change the CMOS setting of your boot-up process from booting first on the A drive (floppy) and then on the C drive (hard drive) to just booting on the C drive. This will not only speed up your boot-up process but also completely eliminate the risk of infecting your hard drive with an infected floppy disk.

    If you need to boot from a floppy you can easily change the settings back and reboot from the A drive. Please note: an infected non-bootable floppy disk can just as easily infect your hard drive as would an infected bootable one.
  6. Don't allow your web browser to automatically run programs, such as Microsoft Word, through its e-mail program. Configure your browser to launch WordPad or Notepad instead. One of the biggest and growing threats is the macro virus, which is spread through data processing and spreadsheet programs
  7. Configure your web browsers to disable ActiveX, Java, and Javascript. You'll lose some of the fun the Web's been known for, but you'll save your computer from contracting a virus and speed up your connection.
  8. Know that the only way a virus spreads is either by launching an infected file or by booting an infected disk. You can not get a virus by simply being online or by reading e-mail. You have to download and launch an infected file before it will spread. Therefore, do not launch any unsolicited executable files sent via e-mail.
  9. Using an updated antivirus program, scan all new software for viruses before installing them on your hard drive. Even shrink-wrapped software from major publishers has been known to contain viruses.
  10. Be aware of hoaxes and scams. A common type of scam targeting computer users is known as a tech support scam. The Federal Trade Commission (FTC) has a guide to help you identify and avoid tech support scams.
  11. Viruses are not the only type of programs that are written solely to cripple computer systems or to use a computer in an unauthorized way. Other malicious programs are logic bombs, Trojan horses, and worms.

More help with viruses

The Virus Bulletin offers a list of viruses that are floating through the computer world at present. The site also offers the opportunity to report viruses, should you be unfortunate enough to encounter a new one firsthand.

If your computer is not on a network, and you never, ever install new programs or download files from the internet, or open email attachments, you likely don't have to worry about viruses. 

But that's like living in a sealed bubble. Most of us have to go out into public every day, where we're subject to the germs carried by others (though natural immunities will usually protect us from most of them).

Likewise, most people also have to update their software and are interested in communication and information from others. Luckily, there are some preventions and cures for even the nastiest of viruses.