On what you want to do. Remember, it's a Microsoft programme, but the best way of being safe is to use an anti-virus suit. I use Trend Micro Internet Security, this has it's own firewall, will run e-mail scans on incoming AND outgoing mail, and has a real time scan system (amongst other things).
As for Norton, just read some of the comments posted on these forums about that system, it's almost impossible to remove.
I would be inclined to first get a trial package from one of the other anti-virus companies, to see what it's like, then back up ALL your irreplaceable data (Word files, e-mails and the like), if you haven't already got them, download Spybot S & D and Ad-aware - both free. Backup all your downloads as well, then set to work and be prepared to re-install all the programmes again. That's not too bad, because the private data you will eventually need you already have backed up.
Running: Windows XP Pro, SP2
I run Norton Antivirus(SystemWorks)and Norton Firewall. What I'd like to know is, whether or not the Windows Firewall that comes with my Operating system is sufficient enough by itself that I can discontinue the use of the Norton Firewall without worry of putting my computer in danger. I'm pretty sure an answer from the Norton and Microsoft people would be biased. So far, I haven't been able to find enough evidence on this topic to make be comfortable enough to switch from Norton firewall to Windows firewall, but I sure would like to do so.
Please help if you can.