I was in the same boat as you. I had Norton 2003 and my subscription was running out, so I thought that I would buy the Norton 2005 version. IT WAS A HUGE MISTAKE!!!
I followed the directions that said that the previous version had to be removed before installing the 2005 version. I used the add/remove and thought that it was removed completely. When I tried to install Norton 2005 I kept getting a failure message, and couldn't install it. I went to the Symantec web site and tried everything that they suggested including 2 separate downloaded tools from them that was supposed to fix this very problem. It didn't work. Neither did removing all entries in my registry, removing all references that I could find on my computer that had anything to do with Norton or Symantec. I went to several computer forums, tried all the suggestions, and got exactly the same failure to install message. I spent many many hours trying to install it, and finally gave up.
I returned the program to the merchant I purchased it from and got my money back.
I am fortunate to have the Roxio version of "Goback" on my computer so I reverted my drive to a time before I had attempted to install Norton 2005. I then just renewed my subscription with Norton's 2003. I figure that I'll probably have another computer before the next time it needs to be renewed.
All I can say is that Norton AV 2005 is the worse computer program I've ever encountered. I've seen the same complaint from others who've tried to install this program. I guess Norton has gotten big enough that they can market a product this bad and get away with it.
As far as the Norton 2003 version not being supported, I've never had much luck with the support from Symantec/Norton on their products anyway.
Edited by gaelic123, 28 March 2005 - 11:54 PM.