The Conficker C computer worm is expected to activate on April Fool's Day. The malicious program already is thought to have infected between 5 million and 10 million computers. Those infections haven't spawned many symptoms, but on April 1 a master computer is scheduled to gain control of these zombie machines, said Don DeBolt, director of threat research for CA, a New York-based IT and software company. The program could delete all of the files on a person's computer, use zombie PCs -- those controlled by a master -- to overwhelm and shut down Web sites or monitor a person's keyboard strokes to collect private information like passwords or bank account information, experts said.

The anti-worm researchers have banded together in a group they call the Conficker Cabal. Members are searching for the malicious software program's author and for ways to do damage control if he or she can't be stopped. They're motivated in part by a $250,000 bounty from Microsoft and also by what seems to be a sort of Dick Tracy ethic.