Windows 10. I left the system on when I went to bed. I had Opera, two notepads, I think one VLC, and maybe a image viewer (One Photo Viewer), open. This morning, good morning, I found the system at the log-in screen. I assumed the system rebooted, perhaps a temp blackout or whatever. I log in and I find every program-window closed, as expected, apart from the two notepads. One of them blank, one of them with a number on it. Both intact. The number was the same I typed the day before even though I never saved the file. So, any ideas?