My Zone Alarm Free (v. 9.1.x) on my Windows 7 machine was sucking up computer resources and my PC was coming to a grinding halt with ZA running. It was pulling lots of CPU for whatever reason, so I thought I'd install the newer version. Over the course of using ZA products I've noted new version sometimes fix slowness issues, loading speed at startup, etc.
Simple install wouldn't work... created a temp file that sucked up tons of resources and the install exe just sat there. Tried to uninstall using the control panel option and it did the same thing. Temp file eating up resources, exe that sits there. Used the uninstall option in the program group, same thing... temp file sucking up tons of resources and an exe that sits there doing nothing. Tried in safe mode... same thing. Then I downloaded the uninstall utility from Zone Alarm... same thing as before.
What worked was the manual uninstall I found in the Zone Alarm FAQ. I followed the Vista instructions. As manual uninstalls go, it was fairly easy and standard stuff. Delete program folder, clear some other stuff, delete driver files and registry keys... done. That of course worked and I was able to install the latest (not Beta) build.
FWIW, it seems to be working and is not sucking up resources like the previous install was. So if your older version isn't upgrading, will not uninstall... hopefully this helps you somehow.