Two days ago I took advantage of a free "upgrade" to NIS (I think I was only on NAV before); the version appears in file manager as NIS 21.5.0.19. However whenever I have tried to start my PC since then, it apparently loads OK as far as showing the icons on the desktop, but doesn't allow anything to run - even the Start button won't work (so I have to perform hard switch off). I'm using Windows XP SP2, which I know is long in the tooth - I'm waiting for W10 to upgrade as I don't like Windows 8 at all! I can however enter Safe mode and everything seems to run OK then (in as far as it ever does in safe mode - still I have been able to take a full data backup). However trying to start in the last known good configuration also fails to work. The Norton icon doesn't appear on the bottom status bar, which suggests that it's not managing to load fully. As well as installing NIS I had to download an additional Windows XP root certificate to permit Norton to install itself. Any suggestions? Should I try uninstalling NIS, but in that case what do I use for protection?