Brian Livingston, editorial director of Windows Secrets, an electronic newsletter about the Microsoft program, said in an interview, “Prosecutors should be chasing the maker of these spyware programs, not hapless teachers who have nothing to do with the images.”

Ms. Amero’s husband, Wes Volle, was emphatic in saying she was clueless about computers and was in over her head once the pop-ups began. Mr. Volle, a graphics designer, accused the school system of sacrificing his wife to deflect attention from its own failure to install effective filters on its computers.

A chat room on the Web site for The Norwich Bulletin has at least 10 pages of comments, including one from a person who had just returned home to the Netherlands after a vacation in New York and Vermont. "Holland is awaiting the outcome of this trial in a state of total disbelief," the poster wrote. "Has the USA lost it sense of reality?"