Protecting Against Computer Viruses

An outside computer attack isn't the only bad thing that can happen to your system. Far more likely is an attack from within, in the form of a computer virus infection.

In many ways, a computer virus actually is similar to a biological virus. A biological virus invades your body's system and replicates itself, causing all sorts of damage to the host (you). Likewise, a computer virus invades your computer's system, replicates itself, and causes untold damage to the host (your computer).

Like biological viruses, computer viruses can be destructive, or they can simply be annoying. Just as you try to protect your own body from biological viruses and find a cure when you become infected, you want to protect your computer from computer viruses and find a cure if its system ever becomes infected.

Bottom line? A computer virus is a computer program that places copies of itself in other programs on your system, or somehow manipulates other files on your system.

Are You Infected?

Computer viruses can infect program files, the macro code found in some data files, or the HTML code used to create a Web page. Plain-text e-mail messages are not capable of being infected, although HTML e-mail and e-mail attachments can contain viruses.

How do you know whether your computer system has been infected with a virus? You may notice one or more of the following symptoms:

• Your system begins to act sluggish.

• Your system fails to boot.

• Normally well-behaved programs start operating erratically or crash intermittently.

• Friends report that they've received a strange e-mail message from you and the message came with a suspicious file attached.

• Files you know you haven't erased turn up missing.

• Common program files appear to have grown in size since your last analysis.

• Strange messages or graphics appear on your computer's screen.

If your computer exhibits one or more of these symptoms especially if you've just downloaded a file or received a suspicious e-mail message the prognosis is not good. Your computer is probably infected.

How to Catch a Virus

Whenever you share data with another computer or computer user, you risk exposing your computer to potential viruses. There are many ways you can share data, and many ways a virus can be transmitted, including:

• Opening files attached to an e-mail message even a message that appears to come from someone you know

• Opening a file that was downloaded from the Internet

• Reading an HTML e-mail message

• Viewing a Web page in your Web browser

• Sharing a file with someone else on your network

• Sharing a data disk with another user

In other words, practically anything you do with your computer on a regular basis can be a means to transmit a virus.

Scary, isn't it?

Practicing Safe Computing

Because you're not going to completely quit doing any of these activities, you'll never be 100% safe from the threat of computer viruses. There are, however, some steps you can take to reduce your risk:

• Don't open unsolicited e-mail attachments, especially from people you don't know. If you get an unsolicited e-mail message from someone you've never heard of, and that message includes an attachment (a Word document, or an executable program), don't open the attachment! The attached Word file could contain a macro virus, and the attached program could wipe out your entire hard disk. In fact, I caution against opening unsolicited attachments from anyone even people you know. That's because some viruses are set up to replicate themselves through e-mail messages that are sent out without the user's knowledge; the message might look like it's coming from a friend or colleague, but in reality be from a virus-infected computer. (In other words, don't open any attachments you weren't expecting.) And if you want to be even safer, configure Outlook Express to reject any potentially virus-bearing attachments.
  
  
• Download programs only from reliable sites. If you're connecting to a non-commercial Web site run out of some guy's basement, avoid the temptation to download any files from that site. If you must download files from the Internet, use only those established and reliable Web sites (such as CNET's Download.com or the ZDNet Software Library) that actually check their files for viruses before they post them for downloading.
  
  
• Don't execute programs you find in Usenet newsgroups. Newsgroup postings often contain attachments of various types. Executing a program "blind" from an anonymous newsgroup poster is just asking for trouble.
  
  
• Don't execute programs sent to you via instant messaging or in chat rooms. Along the same lines, virus writers like to use instant messaging to spread their infectious programs or send viruses to unwitting users in online chat rooms. This is especially dangerous, because you often don't know who exactly it is you're chatting with. The best approach is to just say no and never, ever accept files when chatting.
  
  
• Use antivirus software. Antivirus programs protect you against all types of viruses including both executable and macro viruses. Purchase, install, and run a program such as Norton AntiVirus or McAfee VirusScan, and then let the antivirus program check all new files downloaded to or copied to your system.
  
  
• Share disks and files only with users you know and trust. If you don't know where a disk comes from, don't stick it in your computer's disk drive. The same with files sent over your network, or via e-mail. Unless you know for sure that the file is safe, delete it.
  
  

These precautions, taken together, should provide good insurance against the threat of computer viruses.

Using an Antivirus Program

Antivirus software programs are capable of detecting known viruses and protecting your system against new, unknown viruses. These programs check your system for viruses each time your system is booted, and can be configured to check any programs you download from the Internet.

Unfortunately, Windows XP doesn't include a built-in antivirus utility. (It includes everything else and I'd much rather have antivirus protection than online photo finishing!) Fortunately, you can find several popular antivirus programs at your local computer software retailer, or online. My favorites are McAfee VirusScan (www.mcafee.com) and Norton AntiVirus (www.symantec.com). But installing the antivirus program isn't enough you also have to religiously download the program's definition updates, to keep the database of known viruses up-to-date. With new viruses being written every week, it's no good to have an antivirus program that's several months out of date!

Recovering from a Virus Attack

What should you do if a virus has infected your computer? A lot depends on the type of virus you've been blessed with, and the damage that it has done.

TIP

One way to avoid spyware is to not use peer-to-peer file trading networks; their file-trading software is often infested with spyware.

If your system is still working and you have full access to your hard disk, you can use one of the antivirus programs to "clean" infected files on your system. If specific files can't be cleaned, then they should be deleted.

If you can't start your system or access your hard disk, then you'll have to take your system into a repair center that can use a hard disk utility program to repair/rebuild/restore your hard disk. After your system is up-and-running again, you should also run an antivirus program to perform additional cleaning.

Even if you can get your system up-and-running again, you still run the risk of losing key data files. If your system has been hit, you may have to essentially start from scratch with a "fresh" system, meaning you'd lose any data that wasn't previously backed up. That's one of the main reasons everyone hates viruses.