Cori Hartje, director of Microsoft's Genuine Software Initiative, remains confident that SPP, along with another effort by Microsoft to clamp down on the abuse of corporate volume license keys by pirates, can reduce the rate of piracy of Microsoft's latest products compared to previous ones.

But the company is taking no chances, fighting back on multiple fronts. To distract downloaders who may only be seeking a sneak peek at the new software, the company's offering free online test drives of Vista and 60-day trials of Office 2007.

To reach young people, who are the most enthusiastic users of P2P, Microsoft is putting comics up on the Web, mostly in foreign languages, decrying software piracy.

And on Monday, the company released statistics purporting to show that users downloading pirated software from P2P networks are at great risk infecting themselves with viruses or spyware.

According to an October 2006 report conducted by IDC and commissioned by Microsoft, nearly 60 percent of key generators and crack tools downloaded from P2P networks contained malicious or unwanted software. Similarly, one quarter of Web sites offering key generators -- software that create alphanumeric strings that users can type in to activate their pirated Microsoft software -- had such hidden software.