As a general advice: Stay clear of so-called "security suits", "optimizing suits" and other voodoo software. Including virus scanners. They always tinker with the system in an unpredictable way, often ruining basic system functions on the way. Many, if not most problems people have with Windows - especially when updating - are caused by these "security tools". These days, Windows is quite competent to protect and manage itself, if you just let it do its job. Of course, it still can't protect you from bad mistakes, like starting an executable from an unknown source, but that's always on you anyway. A third-party virus scanner just gives you a false sense of security, which makes people think "oh well, I can just start this attachment on this mail, I'm safe, because I have this security software installed!" ... and BAM!.