So while browsing the internet I have had the computer pop up to alert me that a program has downloaded itself. The first was PerformanceOptimizer which shrunk my screen and "informed me about the dangers of viruses"... Then it force downloaded itself and my downloads stack showed me the .exe file. I removed and ran clamXav. Now the same thing happened but today it called itself Antivirus 2009. I force quit Safari and nothing downloaded to my stack. So now I'm curious... is this how others here notice these attempts that are aimed at PC users? How do you guys notice the attempts to infect your computer? On a personal note, should I look into something since I've had 2 similar experiences with what could be the same program?