if you still want to solve this issue without re-istalling download hijack this from the following URL and send me the logs or post them in the forum.

http://www.spywareinfo.com/downloads.php?cat=sp#det

I would also NOT suggest reformatting because something caused this issue and you need to resolve it incase it happens again, I mean if you hear an engine knock to do establish what it is or just rebuild ?
The problem with reinstalling is that the assumption is being made that you have all the drivers and software the laptop requires which may not be the case, if the laptop is wireless the native driver support for this in WindowsXP is poor which means you could find yourself without a net conection and issues which still require resolving which makes this harder.

If you want to disucss this or require assistance I would suggest checking out spywareinfo forums alternatively I would be willing to help through ICQ or AOL messenger

BTW norton is horrible, it eats up system resources and performs badly imho