If you are plagued with LOTS of popups becuase you actually have spyware and malware on your system (and it sounds like you do if you are repeatedly running Spybot and CWSShredder), then using a popup stopper is like putting a band-aid over a skin cancer.
Sure, you've hidden the problem from view... for now... but the problem will soon grow, and its visible effects will overwhelm the popup stopper like that skin cancer growing past the band-aid, and then one day your system won't boot and will be dead in the water.
-Llama