go to "run" and type "msconfig" and hit 'enter.'
This will bring up your system configuration. There should be a tab on the right labeled "startup." From there, you can pick and choose what programs will startup in that system tray. (the place with all the icons by the clock)
The list may look intimidating at first, but the best thing to do is uncheck the things you KNOW you don't want. For example, you might see something like realplayer.exe. You can uncheck that. Anything else you're unsure of, leave it there. But I'm sure an uber-techie will be along soon to tell you all the exact file names you can disable.
Edit: You might want to enable the Norton Autoprotect, though just to be safe.