Internet Explorer 8 "not responding" when symantec intrusion prevention is enabled

No problem with the system ever before.  The problem started today. 

The computer is less than 2 months old (Sep 29, 2010)

No updates or new programs loaded that I am aware of.

Last Windows update was Oct 29, 2010

 

Norton was pre-installed on computer and running.

 

Running IE 8 version 8.0.7600.16385  32 bit

Windows 7 Home Premium 64 bit

 

Any ideas?  I have very little computer experience.  So please explain what I need to do- step by step.