These quick registry modifications will remove the "This add-on is managed by your administrator" warning from the IE Addons management section.
Please note that we do not reccommend that anyone "play" in the Windows Registry, it is a very fragile thing and shouldn't be messed with. That being said, we cannot be held responsible for you toasting your machine.
We recommend that you backup your registry before playing around in it. You never know when you'll need to restore it
(Click "Start" then "run" then enter "regedit" then) Navigate to:
Ensure that there are no values presant; on a "clean" machine there should be no values. Anything presant will be disabled in the "add-ins" box. If something is presant, delete the value (be sure to leave the CLSID key).
Now, navigate to:
Ensure that there isn't a value entitled "RestrictToList"; if there is, nuke it.
Now, if you've followed the above you should now quit Regedit and open the IE Addons page to see your addons all unlocked; if they are not, you did something wrong, restore from backup and try again.