steer clear of Norton! unless you want to be held to ransom by your own computer after a few months use, its a horrible program just type in 'problem with norton' into google and you will be horrified at the amount of people asking for help.
If you have XP with sp2 then switch on your firewall and install AVG free version
its by far the best value (its free) and with xp firewall it is extremely simple
find it here:
http://free.grisoft.com/
BTW its worth mentioning that its untrue that companies use Norton...companies use a corporate version which is utterly different from the version for individual users.
M