Norton Internet Security 2005 Problem

[IanE]

So I get the above message about 50% of the time when I turn on my computer, and when it does happen I can't access the internet and there's absolutely no traffic flow. It happened randomly one day, but I can get it to go away if I disable NIS2005 or if I restart the computer...

Any got bright ideas for this one or need any more specific answers? It hasn't happened before and I've had the same computer configuration for months.