My faithful old Win 7 machine has a 297-GB primary hard drive, which Windows tells me is almost entirely full. But trying to find where I could delete files, I checked the properties of EVERY directory, and the data volume numbers add up to less than 150 GB. So I have to conclude that somehow some invisible (and probably evil) force is using my drive and hogging my resources. I'm also noticing, in Windows' Task Manager, the running processes never seem to be accounting for enough RAM to almost routinely max out what's available. I have Kaspersky as my anti-malware application, and it never seems to spot anything remarkable. Can anyone suggest a way to find whatever it is that's hiding from Windows, so I can hunt it down and kill it?