It's bad enough when crooks exploit bugs to ruin a home computer, but the consequences of a successful attack can be much worse. A substitute teacher in Norwich, Connecticut, found that out when a computer she was using in her classroom suddenly started showing pornographic pop-up ads to everyone in the class. She now faces up to 40 years in prison after being convicted of willfully showing her students the images. A security expert hired by her defense, however, says he found malicious software on the PC. Read on at PCWorld