SP2 does have some issues with certain things I had an issue with my HP software.
Have you had Netscape installed before or is this a new problem? was it installed before or after SP2. I had to install my Hp software before I installed SP2, and all was ok.
I would try calling netscape and see what they say first. I am not to familar with netscape I use msn and comcast.
When you installed it did you turn of your AV? Sometimes this could cause a problem too.
Hope this helps but it is hard with out any kind of error messages or anything like that.
Try to look here (#4) http://docs.sun.com/source/817-1646-10/troubleshooting.html