Problem after Product Update

After receiving the recent Product Update, my internet usage went out of control.  Whenever I was connected to the internet there was constant data transfer causing my broadband usage to skyrocket.  I looked at the task manager and noticed that a couple of Norton files were constantly working, so I uninstalled NAV and the problem went away.  This has happened on 2 computers, on a satellite connection and a dial up connection, so I don't think that matters and the problem didn't start until I got the 18.5.0.125 Norton update on both computers.  So my questions are, if I re-install NAV, will the problem just come back?  And, if so, is there anything I can do to fix it?  Thanks.