you mean foundstone?
http://www.foundstone.com/knowledge/proddesc/fscan.html
this is a 'port scanner', people use it to see a list of open services on servers to look for applications they can exploit/hack. most likely there is another program installed which uses fscan to do the scan, then sends the result somewhere else. it may be remotely controlled, ie someone initiates scans on an individual basis, but it probably just scans a pre-defined ip range all day long (probably dsl or cable modem addresses) and reports to someone as soon as a it finds a new host with a set of services which are possibly exploitable. you need to run a virus scanner to start off with, if that doesn't find anything, post again and i'll help you further.