Hello there, I'm not sure if any can diagnose this issue, or how seriously I should take the advice, but I will try my best to describe the topic's incident. On last Thursday, when I woke up the laptop to resume Windows (it had powered down due to my being away for a while), a message was on the screen saying that the computer was locked by the user. It asked for an id and password. I did not fill anything in and just clicked OK. The computer then seemed to go back to normal, and brought everything back up. But in truth it started to act very strange. For example, the Start menu would only bring up a black box. A video I had had open played very choppily. Also, words would not type properly in a Document. A message kept popping up when I tried to save it, saying something about there not being sufficient memory! A similar message came up when I tried hitting Ctrl/Alt/Del. The last but not least thing is that a document I was writing in, when it wouldn't save, I just closed it; and now I can't find it at all. I only see a strange coded file conversion-like thing in place of the document. Is there a reason that all of this happened? As a last seperate question, does anyone know what Behavior Shield is in avast antivirus internet security? I hope that this was adequate. Thank you in advance.