I had hassles trying to update AVG from 7.1 - many times each update till I eventually gave up - finally they recently sent an auto update popup advice that 7.1 is no longer to be supported as of 2007.

So I had another go, and Lo! version 7.5 installed without hassle.

Lots of nice new things like being able to look at Mailwasher downloads, etc.

So look at AVG 7.5 - free version.