Could you please post in your Signature/Profile information about your system (OS, RAM, security software -- AV/FW/other security software real-time and on-demand, and browser(s) so that we can help you better? Thank you.
Is this version of Avast an upgrade or a clean install. Otherwise, is Avast working fine for you?
Have you changed any of your Avast settings from default? If so, what have you changed?