Like apglenn, I have ZA ES I also only have Windows Defender after following instructions to remove other tools (ad aware, spybot). I have Windows Vista Home Premium 64 bit. I tried to install the latest update prompted for by ZA ES. The update only made it through about 70% and froze. When I rebooted, my Internet service was down and ZA ES did not work. The only reason I am able to type this is because I used Windows restore function to restore to a prior date, which rolled my system back to ZA ES