I received a computer that was opening ads after loading webpages. The browsers (Chrome and IE) were redirecting to adfoc.us page. The computer was recently reinstalled with Windows 7 and had Microsoft Security Essentials installed. The owner was for a few days in Italy and returned home (in Romania) with this problem.
The strange thing is that his phone (Android OS) is having redirects to adfoc.us both in Italy and Romania.