Unfortunately, you've not told use the file types or their exact locations.. Just an example, if some of those compressed files are in the System Restore volumes, then they are protected and your AV program could be identifying some of the old viruses as a bad file.. In order to delete such System Restore volumes (System Volume Information directory), temporarily disable SR using the instructions in the link below:

How To Disable System Restore

Hope this helps.

Grif