When an anti-virus or security program quarantines
a file by renaming and moving it into a virus vault (chest) or a dedicated quarantine folder, that file is essentially disabled and prevented from causing any harm to your system. The quarantined file is safely held there and no longer a threat
until you take action to delete it. One reason for doing this is to prevent deletion of a crucial file that may have been flagged as a "false positive
" especially if the scanner uses heuristic analysis
technology. Heuristics is the ability of a scanning program to detect possible new variants of malware
before the vendor can get samples and update the program's definitions for detection. Heuristics uses non-specific detection methods to find new or unknown malware which allows the anti-virus to detect and stop if before doing any harm to your system. The disadvantage to using heuristics is that it is not as reliable as signature-based detection (blacklisting) and can potentially increase the chances that a non-malicious program is flagged as suspicious or infected. If that is the case, then you can restore the file and add it to the exclusion or ignore list. Doing this also allows you to view and investigate the files while keeping them from harming your computer. Quarantine is just an added safety measure
. When the quarantined file is known to be malicious
, you can delete
it at any time usually by launching the program which removed it, going to the Quarantine tab, and choosing the option to delete.
Creating a new Restore Point and purging the old as boopme instructs, would have removed those files if your anti-virus was not able to quarantine them. In any case, doing as he says still should be done as the last step after disinfecting your system so you have a clean working state to return to if needed.