I don't know about anyone else, but I lock my computer almost every time I leave it, because I want to leave a process running while I do something else, but I don't want somebody to pull some stupid prank on my computer that I can prevent (i.e. I was told that some of my dorm wingmates snuck into my room and tried to block Youtube on my computer but couldn't...this was before I started locking my computer...don't know if it is true). Now I can't do this thanks to the recent Windows 7 update, because it halts all ongoing processes while locked. So far this has happened to Windows Live Movie Maker while it was outputting a file, and Quicktime while it was downloading a 720p movie (it didn't finish downloading because of this, and when I came back, the audio would play but the video wouldn't).