Avast is an another popular anti-virus for free user. Now I am going to inform you the way of download of avast anti-virus update manually. Avast update file is known as VPS. Go to the home page of Avast antivirus or follow the link http://avast.com.
When Index page of Avast will open, click to support from upper menu and choose updates from the right side bar. Now download Update avast! VPS.
Now download Update for your Avast Product. You will find two update file for 'avast! 5 VPS update, version 5.0.0' and 'avast! 4 VPS update (old product), version 4.8.0' respectively .
If you are a free user of Avast Antivirus , you need to use a key for your product and it is also free from avast. Just you need to register and they will mail you a product key to you. To register for free choose 'Get a free license' from Support page of Avast. Go http://www.avast.com/registration-free-antivirus.php to access the registration page directly.