Fake Online scan webpage not detected!

I was surfing on the internet when I clicked on a website accidently and it suddenly opened an online fake

 

scan page and it was showing me exaggerated reports of how my system was full of viruses .

Here is the screenshot

 

windowssecurityalert.jpg

 

I am wondering that why did NIS not block the webpage from opening ? As seen from the screenshot the Safe Web mark is showing that the site is safe !!!

 

How can it be ?What was that multilayered NIS protection system was doing ???

Message Edited by Shridhar on 05-28-2009 07:08 PM
<<Edit: Image resized to fit into the screen.>>
Message Edited by TomV on 05-29-2009 02:37 AM