Rogue software and malware writers are continuing to innovate and customize their social engineering attacks, to make them more believable to users.
Now you have a scareware, presumably from the same team which made another rogue Windows 7 Scanner, that looks like and imitates Microsoft Updates window.
This page is a replica of the real Microsoft Update page which one sees when you access it through the Internet Explorer. However this page comes up when you surf using Firefox.
The real Microsoft Update requires Internet Explorer.