I don't particularly care for Norton,had it and removed it.
Maybe its a firewall configuration issue,have you checked the firewall settings?
I'm running Vista home premium on my HP laptop. I'ts been running fine since Feb with Norton internet security 07 installed. I've been getting regular updates for Vista and Norton and in the last few days it wont let me get on the net. When I uninstall Norton I can get access no problem. Reinstall Norton and again no access. I've been on to Symantec and tried all of their suggestions but nothing is fixing the problem. I'm only summising that Norton is the problem. I'm glad to try anything suggested.