Thanks for the judgement. As it happens, a "dead" machine was brought in and my colleague determined it just need a Windows reinstallation, there was no actual hardware fault. To go the extra mile he ran a quick scan for lost files thinking how pleased the customer would be that we had saved their data, and immediately saw a bunch of filenames that left no doubt that it was child porn. We locked the machine in the safe and rang the police. I can sleep at night over that one.