Theoretically Norton 360 will manage everything. Anti malware and firewall as well as scan everything in sight. This alone can slow the PC down considerably. When you add the other progams - they fight for memory to say the least.
I confess to personal prejudice, I don't like paying for something like Norton when very good freebies are there for downloading. Emphasising it is a personal view ..... I would uninstall Norton (Using their own uninstaller which you can download from their site), Windows own uninstaller doesn't work well with this application.
If you choose to keep an up to date Norton, then remove all the others - pdq
I use (with XP) the all free versions of Avast for anti-malware, and Zone Alarm as a firewall. I occasionally run Malwarebytes as a straight on-demand scan , but have not so far found anything passing through the first ones.