Think there's no malicious software on your computer? PC Magazine thinks you should think again. Scans by ISPs have revealed as many as twenty-eight spyware programs running on the average home computer--like yours. That's a lot of people prying into what's on your PC, and a DSL or cable connection is a virtual welcome mat. But by following Ed Tittel's advice, you can learn how invasions occur, spot an infestation, repair damage that's already done,...