Hopefully one of the moderators can move this to the correct avast! Free/Pro/Suite Forum http://forum.avast.com/index.php?board=2.0.

What do you mean “you can’t open browser or mail” ?
Clearly your are able to open the email program (which isn’t what I take the above to mean) or you wouldn’t be able to even check for or send emails if the program didn’t open.

Have (or did) you another Anti-Virus installed in this system, if so what was it and how did you get rid of it ?

What was your firewall before installing AIS6 ?

EDIT: ~~~~
As a temporary measure stop the Web Shield that should allow you to brows, without having to disable AIS completely.