NAV 2010 - latest update, big problems

LiveUpdate wanted a restart to install the new version. Rebooted. But Norton would not load - no ccSvcHst processes. Going into Services and trying to start manually gave error -1, could not start. Ran the removal tool, reinstalled it fresh. That went fine, until I changed the default settings back to what I had - aggressive heuristics, no background full scan, ignore cookies, no background defragging. As soon as I clicked APPLY, the PC rebooted itself. Then I couldn’t get logged back in, Windows said my profile was corrupt. Well, after uninstalling NAV 2010 in Safe Mode as Admin, all was well again. What on earth did this release break?