Having read your post I then updated Norton. I should have known better,I have the same problem as you! This is the same thing that happened some while ago with a large download and update.
Normal updates have installed since the last cock up with no problems! When I downloaded it said one update had failed so I restarted and all was o.k. with e-mail. Foolishly,I downloaded again and this time it installed o.k. but when I restarted no e-mail but internet o.k.
I is caused by their own update and is not your fault,I will try to recall what they told me to do last time when I e-mailed them having had to system restore to get it to work. You will find if you restore XP firewall and switch off Norton
your Outlook will work,thus proving my point.
I will post if I get it sorted!!