Some of those who use Microsoft security software received a security patch a couple days ago that lead to malware warnings for users trying to visit Google.com. Softpedia posted a picture of the warning.
On February 14, 2012, an incorrect detection for Exploit:JS/Blacole.BW was introduced. On February 14, 2012, Microsoft released an update that addresses the issue. Signature versions 1.119.1988.0 and higher include this update.
Of course, I am sure Microsoft didn’t mind some of those Google users looking for other search engines to use for the day.