Zone Alarm shouldn't be an issue, but disable it just incase. Norton Personal Firewall should prevent IRC access but gives you an option to allow connections when you try and connect (first time) - if you've done this, again, no problems should occur. However, once again, disable this to make sure it's not the issue.
So, now that you have both ZA and Norton disabled, try and connect.
If it still does not connect you need to include the error message you are receiving.