I have the free version of AVG. When browsing the internet I encountered an avg popup saying that something like blank.survey was stopped by avg because it was infected with malware. I alt+f4 just to be safe to close the popup. I did two deep scans after that with no threats found. My question is this. If avg stops attempted malware infection and the scans show no threats is there any need to reinstall operating system just to be safe? If avg detected a threat and stopped it then even if it had infected my pc the deep scan would be able to detect it as well?