This happened a few days back. I was just browsing my "My Documents" folder, when I noticed a folder missing - My Videos. I panicked, then discovered it was still there when I enabled "show hidden files and folders". But I don't know how it became hidden - I'm sure I didn't do it. It didn't bother me much, but I still don't get how it happened. I'm running windows XP Home (I think..), with AVG, Avast, PC Tools Firewall(although not at that time - I just got this recently), Spybot S&D, Ad-aware, Spywareblaster, and of course, CCleaner. Could this be a cracker trying to get to my PC?