On Access Scanner – special providers to protect:
the most of available E-mail clients,
Instant Messaging – ICQ, Miranda etc.,
Network traffic – Intrusion Setection – lightweight firewall,
P2P protection for Kazza, BitTorrent etc.,
Web shield – monitors and filter all HTTPtraffic,
Script Blocker – checks all scripts running under Windows Scripting Host and Web browsers,
NNTP Scanner – scans all Usenet Newsgroup traffic
and of course all operations with files on PC.

Boot Time Scanner – scans disks in the same way and in the same time as Windows CHKDSK does (on NT/2000/XP only).
avast! can scan inside the huge number of different packers including ZIP, ARJ, RAR etc. even the Outlook Express .dbx files.
Virus Chest – safety isolated folder to store infected, suspicious and even some system files – to restore them.
avast! 4 supports Windows XP SP2 Security Center.
True incremental update files of size under 100 KB are available at least twice a week and within couple of hours in the case of emergency of new virus. avast! automatically checks for new updates – downloads, installs and loads them without restart or logoff.
avast! 4 Pro is available in English, French, German, Italian, Japaneese, Polish, Portuguese, Russian, Spanish and other languages – check avast website to download avast! in your language.