Try using Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system.
Once the Revo Uninstaller finishes its job, restart your PC, start it again and look for WinZIP in the list. It should be removed by now, but it's better to double check. If the software has been removed from your PC, you can continue to install or update other apps.