Not a huge fan of either but Zone Alarm has a tendency to conflict with other apps/hardware, especially networking. Someone here (I think) recommended a GREAT free firewall that you can
download here. I've been using it on both my host and remote PC's for a couple months now and love it. At first, you'll have to deal with some prompts for allowing certain devices to connect but most firewalls do that. Not really an issue after you've permitted the things you use the most.
Give it a whirl but uninstall Zone Alarm first.