Moved to Malware Discussion > Home User Assistance. It isn't a virus. I'm afraid that no antivirus will detect this kind of 'fake anti-malware', you need specialist tools to get rid of them. There is an excellent removal guide available on the web here: http://www.bleepingcomputer.com/virus-removal/remove-win-7-antispyware-2011. Scroll down that page as the first links you see are mostly advertising that helps pay for their extremely useful forums.
They also have removal guides there for a whole host of similar fake anti-malware pests.
Basically to avoid these keep your machine always up to date and be very careful what you download and click on.