As I said, Windows Defender is anti spyware program, and it is not intended to replace an antivirus program. It is included in Vista as well as Windows 7. I get reminded to run a Windows Defender scan all the time in Vista, but not in Windows 7. So when you say "replacing an anti-spyware program with an antivirus program doesn't make much sense!"... I agree with you. I like Avast, and I still use the free version. I have purchased Advanced SystemCare Pro for $19.95 a year