Thanks, I had no idea what "overhead" meant.

You still didn't answer my questions-

1)Can you explain why it has less "overhead"?
O yeah because it uses 1/3 less CPU
Norton and MacAfee uses 75% more computer resorses.
Trend uses 1/3rd of what they use meaning less overhead.

2)What does a anti-virus have to do with file sharing on a closed network? When sharing files the antivirus will scan the files because it see's it as a outside file so , it will scan it.
With trend it knows were it is coming from and on a network it can see if the files is infected.

3)Don't most if not all virus come from a INTERNET connection OR a deliberate insertion of a virus locally?
Yes this is true Trend does all that plus spyware with alot less CPU resorces.