I have the same problem, using ZoneAlarm Extreme. I can hide the ZoneAlarm toolbar, but it reappears when I open a new tab or a new IE window. Should I uninstall and reinstall ZoneAlarm?
ZoneAlarm Extreme 9.0.114 (recently upgraded from 8), including ForceField 18.104.22.168
Internet Explorer 7.0.5730.13 (recently upgraded from 6)
Windows XP Professional SP3