1. C:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\chest (XP location).
C:\ProgramData\AVAST Software\Avast\chest (Vista, Win7, win8.x and later).
This is a protected area where it can't easily be accessed from outside, files are encrypted and renamed to prevent access and running files in the virus chest.
2. Right click on the avast tray icon, select Virus Chest. You can now see the files contained there, they can be restored from the chest, but obviously if they were considered malicious, they would be detected again and but back in the virus chest.
Files can be Restored and added to the exclusions, so avast doesn't alert, but you have to be 100% sure they aren't infected or your system is at risk. The only reason you should be doing this is if you are certain it is a False Positive (FP) and you should send the file to avast for analysis and correction as required.
