From the Wikipedia article:
"ComboFix is an executable software, intended for users with advanced computer skills to run only on occasions where a regular antivirus would not detect certain malware, or where an antivirus cannot update or otherwise function.
This cleaning utility runs itself and scans the entire computer system, including more notable areas such as the registry and the system root files, where most prevalent malware are most likely to hide.
Furthermore, ComboFix also displays a report of malware that were not able to be removed. The report is accepted by many forums, where experienced users analyze them and advise users further steps of action."
http://en.wikipedia.org/wiki/ComboFix
"ComboFix is an executable software, intended for users with advanced computer skills to run only on occasions where a regular antivirus would not detect certain malware, or where an antivirus cannot update or otherwise function.
This cleaning utility runs itself and scans the entire computer system, including more notable areas such as the registry and the system root files, where most prevalent malware are most likely to hide.
Furthermore, ComboFix also displays a report of malware that were not able to be removed. The report is accepted by many forums, where experienced users analyze them and advise users further steps of action."
http://en.wikipedia.org/wiki/ComboFix