Tried to download Avast Pro manual which is a Adobe Reader file and it would lock up Internet Explorer and had to use task manager to close program. Tried turning of behavior shield but did not help. Went to adobe reader and unchecked display in browser and tried again and it worked. Avast Pro 5 will not let adobe reader open a file in browser window but does fine if you just uncheck it. Small bug that I wanted to report so the avast team will have something to work on, like right now they have nothing to do. Of course then discovered I was downloading the 4.8 manual. Did not find the 5.0 manual but did find the quick start guide.