Having used IS for a long time without any trouble, I noticed today that it was a bit behind on definition updates.
I pressed the “update” button, and since then it has been “initializing, please wait…”
I have windows firewall disabled and am using the Avast-firewall. I tried disabling that for a while to see if Avast was blocking itself, but it didn’t help.
Try uninstall it using avast! Uninstall Utility(download link: http://www.avast.com/uninstall-utility). After you uninstall it, reinstall avast! again. You might having problem(s) during avast! virus database installation.