Hello
I suspect Norton Internet Security (NIS) isn't configured properly. NIS was a real bugger when it came to allowing internet access to applications, often it would deny access even if they were configured to have access. upgrading to a newer build would automatically deny access and you would have to reconfigure NIS.
For awhile there back when I was using windows 2000 I was getting non-stop blue screens of death and I couldn't believe my new PC was so unstable. I removed NIS and the problem went away