After doing a thorough scan, the results page came up and only 14 viruses were found out of 151. The other 137, Avast was unable to scan saying that the “Archive is password protected.” And there is only one that can’t be scanned because the “CAB archive is corrupted.”
I assume that the infected files were sent to the chest ?
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.
Many programs (usually security based ones) password protect their files for legitimate reasons such as AdAware and Spybot Search & Destroy, there are others (and avast doesn’t know the password or have any way of using it even if it did know it).
When you run scans with the above programs and you delete harmful entries that they detect, a copy is kept (in quarantine/restore/backup) in case you need to reverse what you did. These are usually password protected, you should do some housekeeping and delete old backup/recovery/quarantine entries (older than two weeks or so), this will reduce the numbers of files that can’t be scanned.
By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.
Files that can’t be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.
There are a lot of packing methods. avast is not being able to unpack the archive and scan the files.
Maybe the file is corrupt, maybe it’s ok but has a ‘strange’ packing method, only this.
Nothing to worry that much.
As Tech said there isn’t much you can do about that if it is corrupt it can’t harm anything. If however it is some exotic packing method, only the program linked to it could open it, e.g. extract it and when extracted avast scans newly created or modified files. So if there were anything untoward avast would have a shot at it then.