Microsoft Tests a Windows Defense

When computing experts say you should never try out beta-test versions of any system-utility software, they're almost always right. A bug in a program that lives in the core of a PC's software could lead to a complete meltdown, not just the usual crashes.

So what's something called Windows Defender (Beta 2) doing on Microsoft's home page, atop the "Popular Downloads" list?

Microsoft first released this free anti-spyware tool as "Windows AntiSpyware" in January 2005, a month after it bought the program's developer, Giant Software Co. After 13 months of development, a few revisions and one name change, this program still isn't finished-- but in that time, Windows Defender has persuaded many users to disregard the rule about beta system utilities.

I can see why. By policing how new programs try to modify Windows, Defender has swatted away much of the spyware I've thrown at it while staying out of the way otherwise. (The unwanted programs it couldn't evict defied the efforts of competing spyware removers, too.)

And it provides something horribly overdue in Windows: a simple way to inspect all the software active on a computer, including those normally hidden from view.

Plus, Windows Defender is a free security tool from Microsoft, the company whose design decisions made it so easy for spyware to invade Windows in the first place. It only seems right for Microsoft to make amends in this way.

Defender is no panacea -- the name alone oversells an application lacking anti-virus or firewall defenses. But it's a sensible way to help keep a Windows 2000 or XP PC free of hidden programs tossing up ads (adware) or tracking your online habits (spyware).

Downloading Defender ( http://www.microsoft.com/windowsdefender ) involves one brief annoyance; you must verify that you're not using a stolen copy of Windows by running a small program, either in your browser or from your hard drive. From then on, it's a quick, restart-free process to install this program, update its spyware database and scan your computer.

As it has revised Defender over the past year, Microsoft has steadily pared away its interface. Its main screen now features a total of nine buttons -- worlds simpler than most competitors.

Unfortunately, you'll have to dig a little deeper to get Defender in its most secure state. It comes preset to grant you veto power only over the actions of known offenders, a take-candy-from-strangers approach that invites trouble. (Older versions of Defender were more aggressive about this.) Click the Tools icon, then select General Settings to fix that oversight.

On a clean PC, Defender stays invisible except when it updates itself and scans the system overnight. Unlike most spyware removers, it correctly distinguishes between browser cookies set by advertising sites-- tiny, easily blocked, inert text files that can't do anything on their own-- and live software code.

If you download from the Web's sketchier sources, Defender will act, depending on when it identifies a new program as spyware. It can flag some as they download, but others go unnoticed until their installers try to force-feed code into the guts of Windows.