What security program did you have installed previously and how was it removed? An improperly removal of a previous security program can interfere with the Norton install.
I purchased (download verion of) Norton Internet Security 2011 from www.amazon.com When I went to download, it just sits there like it's trying to initilize, but it never does. When I exit it/shut it down, it starts a trouble-shooting program. To me, it just simply says to reboot - since I'm using XP....this still did not help!
I'm glad you got it installed properly and thanks for coming back and giving us the follow up. Thanks also for marking the thread solved as now others will be able to find the solution if they have a similar problem.