It looks like Avast Anti-Virus was installed when Avg Anti-virus program, was still active.
That may have caused a conflict [maybe] and a confusion as they were each trying to read the same and different defintion files - the system was infected.

Avg - get a final uninstall on the next reboot.

O4 - HKLM\..\RunOnce: [AvgUninstallURL] cmd.exe /c start http://www.avg.com/ww.special-uninst...feedback-appf?