Help please!! -- Another iTunes won't work thread.

Question

My iTunes has suddenly stopped working, here are the details:
-Windows XP Home Edition
-Norton System Works
There are some VERY strange 'symptoms':
When I run iTunes, the task manager shows it in the PROCESSES list (itunes.exe), yet not on the APPLICATIONS list.
ALSO, when I try to end the process, it doesn't end. NO error messages, no nothing. The confirmation comes up, I hit ok, and the process just stays there.
Another problem is that after I run iTunes, I can no longer launch any other application. Even things that were once running (ie firefox.exe), once closed, can not be opened. (By this, I mean they become like iTunes, and appear only in the processes list). I am forced into completely restarting the computer to use any program that is not open.
-Steps already tried-
1. Scanned for Spyware/Adware using fully updated Spybot S&D, Adaware, and SpywareBlaster.
2. Full System Scan with fully updated Norton System Works (Norton Anti Virus)
3. Disabled every part of Norton, then uninstalled and reinstalled iTunes.
-same exact problems still arise-
Quicktime works fine, just the iTunes which causes problems, all other applications open and close fine.
-Thank you in advance for any support and suggestions-

Answer 1

Norton System Works consists of Norton Protection Center:
One Button Checkup
Norton Utilities
Norton Antivirus
and Norton Ghost
There is no firewall, as in no "personal firewall" feature.
When I disabled Norton to try and reinstall, I completely disabled every feature including "Internet worm protection" and "Spyware Protection" (which is a part of Norton Antivrus)
Product:
http://www.symantec.com/home_homeoffice/products/overview.jsp?pcid=sp&pvid=nswp2 006