un-installing spybot

I need to disable spybot to install an application. I couldn't figure out how to do this so I un-installed it. The spybot application now does not show up in the registry. However, it is obviously still working in my pc. How do I completely un-install this application?

Do I have three guesses? That application would be A. Trend Micro, B. McAfee, C. Kaspersky?

To you it might be obvious that it is still working, to us, it is not, since our magic crystal ball is currently in repair Could you please explain what symptoms lead you to believe that it is still working?