I have just updated my Windows 7 64bit OS to SP1. There is now a weird problem with Avast (free). On boot up, IE9, Firefox & Windows Live all fail to connect to the internet. Disabling Avast, all connect, re-enable Avast and all is still well till the next boot. I have reinstalled Avast with no change & set the firewall to the Windows version. No change.
Uninstall avast from Control Panel (if possible). If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after that.
Run the avast! Uninstall Utility saved on 1. If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after you’ve run it.
Install avast! using the setup saved on 2. Boot.
Register your free copy or add the license key for Pro. Or even upgrade your key from old versions.
Check and post the results. If, for any reason, you did not solve, try doing the step 3 in Safe Mode anyway.
Other option is to repair the installation through Control Panel.
Another one would be disable separate shields to see which one is blocking the connection (I bet on Web Shield or Behavior Shield).
It never broke mine as well - but there have been quite some complaints about this, always same symptoms: boot PC - no browser web. Stop web shield, start browser, enable web shield: all is fine until next reboot. :o And in all cases the “Start Avast services only after other…” did the trick…