The first level of protection is immunization (a passive protection). When you “Immunize”, entries are added to the system Registry. This blocks cookies from some sites, places other sites in the restricted zone and blocks the download/execution of selected ActiveX scripts. If you are interested in learning how this type of blocking works, see Note #1 below. Also Note: If you use Spybot S&D and other products like IE-SPYAD, SpywareBlaster, etc. together, there is an overlap of some of the protection offered. If you undo or disable the protection in one product, it may remove some of the protection installed by the other. You should re-immunize or re-enable the protection in the other products as appropriate.