What fuzeman said. Also note, most firewalls are notorious for blocking the game from the Internet after an update. Just remove the game from your firewall and add it back, after you do the complete install. That should take care of it, unless you are using Norton. Norton's firewall can get in a state where the game will be blocked, permanently, regardless of how you try to add it.
The only know way to correct the Norton problem is to remove Norton, then reinstall it.
