The link that Stuartli has given you is to the free zone alarm FIREWALL. Just download it from the link, remove the old zone alarm via add/remove programs and install it anew from whereever you downloaded it to.
I really cannot see why you are confused, it says on the first line "ZoneAlarm is an easy-to-use firewall that blocks hackers and other unknown threats. " its a firewall, it says its a firewall and the title of the program is ZoneAlarm free.
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