I'm guessing Symantec support is run out of India (land of cheap call centres!) and not wishing to cast any aspersions, but they are shit.
My version of NAV appears with no start and end subscription dates, then crashes. I have been unable to delete three of the install directories because there are files in use, except that the only Symantec product I have is NAV, and this is uninstalled. Support know all this.
Their latest suggestion is to close all programs that are running (duh!) to make sure that nothing is using the files. If NAV is uninstalled, then what the hell else is using Symantec directories?! This is worrying for starters.
Their other suggestion relates to reinstalling the Window's installer, which I told them in a previous email I had already done.