I cannot find a folder in Addons inside WOW.  I cannot find it in software list to use Windows uninstall.  I tried renaming the Cosmos.exe file.  I have written email to Thottbot twice and gotten no response.  I want to get rid of Cosmos and cannot find anywhere that explains how I can regain control of my UI. It tries to take over everything and overpower other addons I chose to install.
Please, how can I stab this thing through the heart?

Somehow I do not think this is the right forum for your question however try going to: http://www.wowwiki.com/Cosmos_Questions There are a few detailed questions on uninstalling cosmos.