Seems to me like the Ad-Blocker is having some issues with Firefox and Chrome 25. When I did an uninstall of Avast! 8 for the 2nd time in a row, because 1st I had issues with registration and avast! icon appearing twice at the bottom right hand corner. 2nd time was with freezing of firefox and chrome. When I uninstalled avast! 8 with the uninstaller utility i restarted it and opened up firefox i saw that it didn't delete the ad blocker for firefox it was still there. So I had to uninstall firefox and reinstall it. Now it's ok, i won't install the ad-blocker for firefox.
When I installed google chrome again the ad blocker appeared (installed) and under settings of Avast! 8 says that ad-blocker in chrome is not installed (that'z a big question mark for me)? So now i uninstalled google chrome and now avast! 8 is not showing google chrome under the list of internet browsers under setting?
During those issues IE10 was not showing me any problems about the ad-blocker and I won't install the ad-blocker for IE10 at all. It was just chrome and firefox! I hope this problem gets fixed in the next update.
