In a perfectly normal and rational world, an epidemic that costs global computer users an average of $10 billion a year might be considered something of a crisis. But because this is a world in which nearly every computer is controlled by Microsoft operating systems and programs, we muddle along--aware of the chaos but unwilling to do anything to remedy the situation.

The cause of this mayhem is virus attacks, which cripple computers and the networks that support them, sometimes for days on end. Systems crash. People can't work. Their companies lose money. Computer Economics, a research and consulting firm, calculates the economic costs of major computer virus attacks so far this year at $10.7 billion. That's based on a formula that takes into account repair times, costs and lost income.

Here's a simple flu shot for your computer: Dump Microsoft Outlook as your e-mail browser. With just one exception, all the vermin on the list of viruses compiled by Computer Economics have one thing in common. They spread through Outlook. Because Microsoft so tightly integrates its software with its operating systems, viruses spread through Outlook can easily infiltrate a computer's most sacred sectors.

Microsoft executives insist they take security seriously. About 2.5 million computers worldwide have been infected with the SirCam virus, which is why you keep getting little messages asking for advice about the enclosed attachments. This was not enabled by a company that takes security seriously.

Microsoft does take adding features to its systems seriously, however, because new features force upgrades, which require new purchases. This also leads to more security flaws.

Microsoft dominates the market, not just with its Windows operating system and Outlook but with its Office suite. With each generation, Microsoft's products become more tightly integrated.

As a result, each new class of viruses can draw on more powerful techniques using the technologies built in to Microsoft's computer systems.

People have been screaming about this for years. "I would never use Outlook. There are too many exploits, too many vulnerabilities and too many people trying to break it," said cryptography expert Bruce Schneier of Counterpane Internet Security Inc.

The first known Word macro virus, dubbed Concept, appeared in 1995 and was created as a warning to Microsoft. Concept didn't set off a malevolent payload when it infected a computer, but it carried a simple message: "That's enough to prove my point."

Or not, as it turned out.

Microsoft's dominance makes this whole mess worse because people creating viruses, worms and Trojan horses design them for the Microsoft environment--Windows, Outlook and Office--to have the best chance of landing in fertile soil. So all smart computer users have to do is till a little salt into the virtual soil.

Viruses that depend on Outlook to propagate can be stopped dead when they hit another e-mail program. There are dozens of alternatives, including Acorn, Allegro, Becky, Calypso, Lotus Notes, Pegasus and Poco. Even Netscape comes with a built-in e-mail application. But probably the most widely used e-mail software after Outlook is Eudora, named after the late short-story writer and novelist Eudora Welty.

Eudora became the dominant alternative e-mail program because Steve Dorner, a student at the University of Illinois in the '80s, gave it away and incorporated new features based on user feedback. Today, it is distributed by Qualcomm Inc. and is used by about 20 million people. It's available in various versions, many of which are free, at http://www.eudora.com.

Eudora is not a perfect piece of software. It has its own soft spots that smart hackers can exploit. But most won't bother.

Hackers like to make a mark when they unleash their mayhem. That means infecting the largest population with a bug that does the most damage. Hackers don't write many Mac viruses because not as many people use Macs.

If the world switched to Eudora to handle its e-mail, the bad guys in the hacking community probably would turn their guns on it. That's probably not going to happen. Microsoft has too tight a grip on the world's computers. In fact, the Los Angeles Times is moving away from a multi-e-mail program environment to one based entirely on Outlook, largely because a homogenous environment lowers support costs.

So Outlook will remain the standard for the foreseeable future, and viruses that exploit it will continue to wreak havoc. Protect your corner of the world--give Outlook the boot.