I was brought a laptop on Friday with a non-functioning copy of AVG. The av installed was AVG 8.0 plus the Windows XP firewall and the users promised me that they had not ignored any warnings from AVG. The machine was brought to me because the AVG reported the updates were corrupt, and had not been used since the warning that the last download had failed to install. I uninstalled AVG using the downloadable uninstall tool from AVG Antivirus and Security Software - Tools download to make sure the registry was clean, made sure there was a recent backup of data files, created a system restore point and then downloaded a fresh copy from AVG Free - Download AVG Anti-Virus Free Edition for Windows XP and Vista and installed it. It refused to install, saying there was an incomplete installation which had to be closed first. No such thing so I chucked my toys out of the pram and installed Avira free edition. An initial scan found heaps of various trojans and virus damaged files, which it cleared up without any further problems. A quick scan with HiJackThis confirmed the system clear. Moral - You sometimes get what you pay for, sometimes not.