I am getting the below attached alert message whenever I am trying to open a new webpage. For very few sites, for example, expert-exchange, I am not getting any alert. But for most of them (including some common websites like Yahoo and Rediff) I am getting this alert. I am using Windows XP, IE6 and Avast Free Home Edition. When my Internet connection is off I do not get any such alert. My computer is "not" running slow.
I would appreciate if anyone can inform me why this is happening and how to fix this problem. I am ready to provide further information if needed.