I haven't encountered a conflict between SpyBot and Norton Internet Security before, and haven't heard of any such known issues, so I don't foresee a problem there. Of course, there shouldn't have been a problem during the upgrade of Norton IS either. Personally, I never leave my security in the hands of a single program, so I'd reinstall the latest version of Spybot and have it as an auxiliary scanner. Norton may not like Spybot's TeaTimer, so if it complains disable that, but always get a second opinion now and then from your old friend.
Hope this helps,
when i renewed my subscription to norton i upgraded to internet security 2006. after downloading it during installation the program told me i would have to remove spybot from my computer before it could finish installing,so i did what it ask. now i think norton can handle any spyware problem but i miss the registry check and the easy startup management of spybot.can i reinstall spybot now or are there other programs that will work with the IS2006 and do the things i want? i have a dell 4500 running xp home ed. SP2.