Norton always ask to reboot almost always after one of there installs, I NEVER use any Norton software from pass experience's...If you do not want to do a total fresh install and want to TRY and save what you have, then you will have to start your pc in safe mode
f8 , next, once you are at your desktop,if you make it that far, you have to remove Norton..If you cannot remove Norton then you will have to do a fresh install..