"Warning customers about viruses and spyware in counterfeit software is a nice PR thing for Microsoft, but for the most part, I doubt that it's really effective," says Paul DeGroot, an analyst at Directions on Microsoft, an independent consulting firm in Kirkland, Wash., who applauds Microsoft's other antipiracy efforts.

Microsoft hopes to scare consumers straight, he says, because efforts to guilt and shame consumers into not downloading, have had little success. Moreover, the company rarely targets end users of counterfeit software with lawsuits for fear of alienating customers.

"Our main concern is preventing pirates from putting counterfeits in the hands of unsuspecting customers," says Matt Lundy, a senior attorney at Microsoft.

The technology advances

P2P technology, meanwhile, has advanced greatly since Microsoft released Windows XP in late 2001. At the time, P2P networks such as Napster and Gnutella were solely used to exchange music files. Since that time, Napster has been closed and re-opened as a legitimate pay music service similar to Apple Inc.'s iTunes. The second-generation Gnutella has waned in popularity because of aging technology and partial neutering by the record companies, which have flooded Gnutella with decoy files masquerading as songs, Ishikawa says.