O.K. I don't want t start a ford / chevy type debate, spybot s&d has ADVANCED settings that should not be used unless you REALLY know what you are doing and the main engine in it was stolen by the makers/sellers of adware, read lots about it here
http://security.kolla.de/news.php?lang=en
I use and update it offen and have NEVER had any problems, puter runs great and fast.