First time poster -- Hope I get it right.-- I've got a Dell 3.6ghz with windows xp. Recently when I fire it up I get the following: "Application failed to initialize ok800106ba, a problem caused Wilndows Defender Service to Stop. To start Service, restart or search Help and Support on how to start a service manually". Restarting didn't help and I can't find the service or how to manually restart it. Am I vulnerable without Defender?