My Vista Home Premium PC has Windows Defender on it. I also had CA Security Center for anti-virus, spam and spyware. I think this came with Roadrunner when I installed it a year ago (can't remember exactly)? Anyway, my subscription to CA has expired but I'm not sure if I need to renew it or not? Or is Defender good enough by itself? I'm connected to the net through a Linksys router. Thanks.