Click OK (hit Enter in Vista).
Click on Startup tab.
Click Disable all
Click Services tab.
Put checkmark in Hide all Microsoft services
Click Disable all.
Restart computer in Normal Mode.
NOTE. If you use different firewall, than Windows firewall, turn Windows firewall on (this is very important part for you, since you're using Norton), just for this test, since your regular firewall won't be running.
If you use Windows firewall, you're fine.
Try to play the game.