Hi!
Sorry for your troubles. This usually means you either have a version of ZoneAlarm that is for XP, or you're having issues installing it. If it's meant for Vista, Vista may not know it, and assumes it isn't compatible. You more than likely have an option after/during install when the compatiblity warning comes up, to ignore it, or install anyways. Or, something similar.
Try deleting it completely off your system if any of it got installed, and try downloading it from here -
http://www.pcworld.com/downloads/file/fid,...scription.html#
That's a link directly to the Vista ONLY download. It should work. Good luck and hope that helped!
Edite: And just to add, I downloaded/installed the Kerio firewall and used it for maybe a couple weeks. Horrible in my opinion. Not too user-friendly, and just wasn't that satisfied with it. I don't recommend it - haven't heard of PCTools though.