AVAST 4.8 AND NOW 5.0,

Avast Free Antivirus / Premium Security
1

I HAVE THE ABILITY TO USE THE UPDATE OF ONE COMPUTER TO UPDATE OTHER COMPUTERS WITHOUT CONNECTING THEM TO THE INTERNET

2

Welcome to forum

To Update from 4.8 to 5.0 just download new setup from http://www.avast.com/download-software#tab2 depending on your license (Free, Pro or upgrade to Internet Security).

To update virus-database download update from: http://www.avast.com/download-update

3

Download the update here: http://www.avast.com/download-update

Or copy 400.vps file from an updated avast installation to a USB stick and transfer it to the \Data folder of the off-line computer (having disabled the avast self-defence module first).