I had the same problem yesterday, when I got a popup error message on bootup saying "auto protect" was off. When I checked the settings for Real Time Protection, they showed Auto-Protection as "off." This setting and it's subsettings were also "greyed out" and I could not click on them to turn them on. I rebooted the system, and auto protect turned on, then turned off in less than a minute, and settings showed off and "greyed out." I had to uninstall NIS 2010, reboot, and re-install.
NIS has been running O.K. today. Keeping fingers crossed.
Norton engineers shoulcheck into this issue, because I have been running NIS 2010 for approximately 40 days with no problems - until yesterday 11/18. I suggest the engineers go back and look into the updates that were available over the last two days 11/17 to 11/18.
Setup: latest version of NIS 2010 17.1.0.19
[edit: Clarified subject to reflect moved post.]