Not sure about this one, but try this:
Click Tools/Internet Optins/Settings/View Objects
Anything in this folder that doesn't say "Installed",
delete it. If any of these things related to the plugin
that you want to delete, then delete it !
Another thing you can do is:
Download, install, *update* and run these two programs:
Ad-aware from
http://www.lavasoft.de/software/adaware/
Spybot from
http://security.kolla.de/ (Remove items
listed in red.)
Additional information at:
Dealing with Unwanted Spyware and Parasites:
http://mvps.org/winhelp2002/unwanted.htm
Note the security recommendations.
Hope it helps, if not post back to this tread...