Doran
Contact Norton and have them update your 360 to the latest release..
I had some library problems.
There is a issue with 360 and MSIE 8 but their latest version fixed it
I don't blame Norton since 360 it was developed before MSIE8 and they are not the only ones having compatibility issues with MSIE  
They did it for me for free and the library problems went away.
I still have alot unexplained crashes but I don't think Norton is the cause.
Hopefully the next SR will fix the.. crash issue...