Did you change your avast settings ?
What is the VPS file version (virus database) number, e.g. 0630-2 (see about avast!) ?
Is your avast being updated (Program Settings, Update (Basic) set to automatic) try a manual update to ensure you are up to date.
Mine is set to ask because I’m on a dial-up connection, automatic is the default and preferred option, the more important options are the ones in the Detailed view, The ‘Show sliding box after automatic update’ being the most important.
Although you say you checked and the Update (Connections) you don’t say what it was set to see image and the arrow.