TrendMicro uninstall

One solution is a registry hack

    HKLM\software\intel\landesk\virusprotect6\currentversion\administratoronly\security

take a look at that key you will see one called UseVPUninstallPassword .. w/ a value of 1. change that to a 0 and try uninstalling. should work.
Here is another registry hack

http://djlizard.net/2007/10/17/272/

another would be possibly found at this link:

http://www.computing.net/answers/windows-2000/trend-micro-uninstall-password/63701.html

Not sure what iteration of TM you are using but there is a way to reset the PW:

http://www.mydigitallife.info/remove-or-reset-trend-micro-officescan-uninstall-password-to-default/

I also use a tool sometimes for hard to remove Software called JV 16 power tools. It is very powerful and should only be deployed by advanced users. it can be found here

http://www.macecraft.com

Cheers

You could also try AppRemover:

http://www.appremover.com/

"...The free AppRemover utility enables the thorough uninstallation of security applications like antivirus and antispyware from your computer..."  

I have used this utility several times with success.

Below is one more application remover for AVG, this from Sun Belt Software who have created Viper and GFI.

http://go.sunbeltsoftware.com/?linkid=1280

Source:
http://www.sunbeltsoftware.com/Business/Agent-Uninstallers/

As per the above link it could remove the following:
AntiVirus version 7
OfficeScan 8.0 & 10.0 agents.
Also removes the following, if installed: Trend PatchInstaller, Trend Threat Management Agent, Trend Cisco Trust Agent, Trend Cisco Trust 802_1x Wired Agent

I hope that would help

Sudeep