I was browsing the MSNBC sports website this morning and the webpage suddenly quit on me, a new page popped up from this antivirus/spam company that was telling me that my Mac was slow due to viruses/spyware. The webpage kept asking me if I wanted to scan my Mac which I clicked No but still it insisted, I couldn't close out the webpage by clicking the red X on the upper left corner so I figure I keep selecting No until it closed but I got to a point where it didn't even give me an option to select No anymore so I had to force quit Safari. Does this type of pop-up also happen in the OS-X platform? Or do I really have some type of virus/spyware in my system? Is there anyway to check since I have noticed that my Mac runs slower then it used to when I first got it back in March (or could it be all the other apps and music that is slowing it down?).