Avast! is an anti-virus program developed by Alwil Software based in Prague, Czech Republic. This program was first released in April 1988. Avast! is one of the first antivirus programs released for Windows x64.
Avast! 4 Home Edition
Avast! 4 Home is one freeware antivirus programs are available for users of Microsoft Windows and Linux. Avast! 4 Home is also targeted to prevent several computer threats, including some programs that are literally not computer viruses such as spyware and even rogue anti-spyware, and also provides recovery database (database recovery) that will recover the data that are infected, rather than remove it. The program also provides text and voice translation for 27 languages.
Avast! 5 Free Edition
Avast! 5 Free Edition is an upgraded version of Avast! 4 Home Edition. In version 5, the function VDRB (database recovery) is removed, but has added functionality Behaviour Shield. In addition, Avast! 5 is also equipped with statistical diagrams. Performance Avast! 5 also has improved.
Sources :http://id.wikipedia.org/wiki/Avast!