WASHINGTON COUNTY (Md.) Public School System is using NetOp School software to provide computer instruction for more than 20,000 students at 42 schools. The software allows instructors to view and monitor each student computer in a lab or media center. A thumbnail image appears on the instructor’s screen and if necessary, the instructor can send a warning message to remind a student to stay on task. It is even possible to block certain software programs and applications, such as instant messaging, completely.