You will notice the avast chest is in three sections:
Infected Files, speaks for itself, any files detected by avast that you chose Move to Chest as the action.
System files, back-up copies of important system files. There are (generally) files in the System Folder of the Chest: command.com, kernel 32.dll and wsock32.dll. During the installation, avast! copies some critical system files into the Chest, under the “System files” category. Those files might cause the operating system to crash if they get infected by a virus. If needed, those files can be restored from the Chest to their original location. Should an unknown virus infect the computer despite the extensive protection from the avast! antivirus package and alter an important system file, it can then be easily restored to its original state. As you can see, this is your case.
User Files, an area for the user to import suspicious files that haven’t been detected so they can do no harm and can be sent by email to Alwil for further analysis.
There is no rush to delete anything from the chest, a protected area where it can do no harm. Anything that you send to the chest you should leave there for a few weeks. If after that time you have suffered no adverse effects from moving these to the chest, scan them again (inside the chest) and if they are still detected as viruses, delete them.
