Hundreds of thousands of websites appear to have been compromised by a massive cyber attack.
The hi-tech criminals used a well-known attack that exploits security loopholes on other sites to insert a link to their website. Those visiting the criminals’ webpage were told that their machines were infected with many different viruses.
In this case Windows stability centre is the name of the infection.
For more details see the BBC web site http://www.bbc.co.uk/news/technology-12933053