Midas,
If I understand you correctly, Avast put the "suspect" files into the Chest.
Right click on the ' A ball" and open up the Avast Anti-Virus.
Click anywhere on the main skin to open up the settings menu.
Open up the chest and look in the Infected files folder.
Highlight the file or files to wish to restore.
Go to the top bar, clck on File, then RESTORE.
This should take care of your dilemma.
Good Luck