First download/install Revo uninstaller application on your computer from http://www.revouninstaller.com/ & then i hope you should be able to uninstall
Trend Micro 2006 personal Firewall using Revo uninstaller if you can't find it under usual Add/remove programs.
Disclaimer : Revo uninstaller is a 3rd Party tool, you download/instal this @ your own risk. However as far as i know this tool hasn't caused any harm to PC.
McAfee Technical Support