NISServ.exe
(Symantec)
Norton Internet Security Service which is installed with both Norton Internet Security and Norton Personal Firewall. It is an essential component of the firewall but we do not know its specific role within the various background tasks of Norton Internet Security and Norton Personal Firewall. NISSERV does not show in the Task List in Windows 95/98/ME as it runs as a transparent task, so you have to run Starter to see it. NISSERV shows as a service under Windows NT4/2000/XP on the other hand.
Recommendation :
Leave alone essential firewall component.