By Ben Elgin
Is your computer suddenly behaving erratically? Sluggish performance, more-frequent computer crashes, and a steady stream of pop-up ads can be symptoms of a spyware infection. In an era when people frequently download music, videos, screensavers, and other programs from the Net, spyware infections have grown all too common. At least half of the world's computers have played host to a spyware program at one time or another, computer security firms estimate.
Determining whether your computer has a problem presents the first challenge. A sluggish network connection or a Web site that spews pop-up ads can sometimes be mistaken for a spyware infestation. Fortunately, there are easy ways to check this. A number of online services offer free spyware-screening programs. But watch out for traps. Some spyware purveyors bundle their deleterious wares with such programs as yet another way to get into people's computers.
Dave Methvin, chief technology officer at computer-screening outfit PC Pitstop, considers the following three free programs reliable: Ad-Aware from Lavasoft, Spybot Search & Destroy, and Microsoft's Windows Defender.
Consumers can turn to a number of heavier-duty security programs that can block and wipe out everything from computer viruses to spyware programs. These programs, which often cost under $100, help chase off infections before they take root. Companies that provide such programs include Computer Associates (CA ), McAfee (MFE ), and Symantec (SYMC ).
Once spyware-free, smart Internet users should attempt to learn how they picked up the unwanted code and modify their behavior accordingly. Surfing habits that have led to one spyware infection will frequently lead to another. "If you've had [spyware] once, there's a good chance you'll get it again," says Methvin.
The basic rule: Exercise more caution when downloading anything from the Internet. If a screensaver or software program touts itself as "Spyware Free," be skeptical. Find and read the user agreement, no matter how lengthy. For consumers who want to learn more about the ways in which spyware can burrow into a computer, PC Pitstop offers ample information.
Elgin is a correspondent with BusinessWeek in San Mateo, Calif.