Hi, i recently changed my Avast password on one computer, and heard an Avast notification several seconds later on a second computer. It had apparently blocked a “virus”, and i wasn’t even using it.
I am frustrated because I cannot find any information of this blocked virus anywhere inside the program??? There is no information about it in the Virus Chest, and i cannot find any logs. I am stumped by this whole thing.
If you have not rebooted since it happend, right click avast tray icon and show last popup
I did reboot 
Look in the log files.
As mentioned above, i cannot find the logs? halp…
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Most logs for avast!, and in this case, its Shield reports are found here:
Windows XP C:\Documents And Settings\All Users\Application Data\AVAST Software\Avast\report
Vista, Win7 & 8 C:\ProgramData\AVAST Software\Avast\report
However to see these folders/files you need to apply " Show hidden files and folders " in Folder Options.
When this is the situation, most probably, it was a webpage blocked by Web Shield, i.e., the connection was dropped. Nothing is kept into Chest.