The solution is to choose an option to scan all files.

Figure 7: Making certain that Norton antivirus scans the Recycle Bin and System Restore (folder _RESTORE) files in Windows ME.

Be sure your antivirus program stays up to date. Every few days most antivirus companies come up with new defenses against new viruses. If you don’t have the updates, you aren’t protected.

Keith Little of PC-Help.org (http://pc-help.org/) explains:

After a new Trojan comes out, antivirus companies can take over a month to update. Within 3 weeks of the release of Back Orifice, I was finding it just about anywhere. It took several weeks before the antivirus companies were able to detect it. You cannot rely on antivirus programs to detect Trojans.

That’s why, despite big security budgets, viruses and worms often clobber giant corporations and military installations.

A computer’s vulnerability depends on its operating system. The various Mac OSs and the applications that run on them are fairly safe. Linux, the operating system beloved of geeks, can be terrible or great, depending on which distribution you buy. The next chapter goes into detail on these alternatives to Windows.

If you run any variety of the Windows operating systems, you are at the highest risk for attacks. That’s because programmers write their malicious programs (malware), including viruses and worms, for the kinds of computers they own. In most cases, that means Windows.

Today the most common way to install a virus is through email attachments. No matter what operating system you run, if you are careless with attachments, you can infect your computer. You say you trust your friend to never send an infected file? A virus can email you from the account of a friend without his or her knowledge.

The most hazardous email program today is Microsoft Outlook, which comes with Microsoft Office. Note that it is not the same as Outlook Express, which comes free with Windows. Malware programmers prefer Outlook because it runs Visual Basic for Applications (VBA). This is a powerful scripting language that invites worm and virus attacks.

Older versions of Outlook will automatically run any attached program if you merely bring it up in the preview window. According to Keith Little, "Outlook is the only email application on the face of the earth that has ever betrayed users to that degree."

Most people use Outlook Express. It is not quite as dangerous as Outlook because it uses a weaker scripting language, VBScript. Still, it is powerful enough for hackers. For some examples of Outlook Express exploits, see http://www.malware.com/idiot$.html.

If you must use either Outlook or Outlook Express, be sure to upgrade to the latest version at http://windowsupdate.microsoft.com/. Be sure to check regularly for new upgrades.