Comment What OS? And how annoying? (Score 3, Informative) 366
What OS are you running? You could create a simple bat script that pops up an annoying message every 20 or 30 minutes to show your students an "infected' machine.
"Who cares if it doesn't do anything? It was made with our new Triple-Iso-Bifurcated-Krypton-Gate-MOS process ..."