How to Remove Pop-Up urging upgrade to NAV 2011

I have a 3-PC license for Norton AntiVirus 2010. Recently, they started popping up a window, urging me to do a free upgrade to NAV 2011, based on a download that was already done for me.  I did the upgrade on one workstation, but it didn't go smoothly and I don't want to risk potential problems by upgrading the remaining two. Anybody know how to permanently turn off that pesky pop-up window that gives me only to options:  install now or remind me later?

 

Related question -- anybody know where to download a complete, technical user guide?  The 330kB, 40-page "nav_2011-retail-ug.pdf"  version available from technical support is worthless and doesn't even list or describe the various controls/settings available within the program. Who knows, if I felt more confident about the product, I might actually want to upgrade my other two workstations ...  Thanks for support on both matters.  Rob