In the past few days, I've had 2 random occurrences on certain sites where a new tab would pop up with text in the middle of the screen saying Microsoft Security Essentials has detected potential threats and I need to clean out my computer immediately to prevent the system crash. There is also a something that says "clean computer" that can be clicked. Well as far as I know I don't even have MSE. I have Avira and Malwarebytes so I'm assuming this is just some BS scam. What exactly is it?