I had a problem with activating Norton software (Internet Security and System Works) after 6 Installations as I have had to reformat and reinstall a few times, so rather than pay for a new copy I just installed the 2003 versions which do not need to be activated.  Also after a year when it stops working I rekon you can just uninstall the software and reinstall it to get extra years free, as I think its a con that symantec want you to pay a subscription each year.