This news story mentions a virus called DNSChanger that is supposed to have lain dormant on systems for up to a year, and is due to hit on Monday apparently.
There's a link in the story to a gov.au website to check your system to see if you're affected.
I don't normally post the multitude of virus warnings that come past, but this one seems to be legit, at least to a brief check of it.
http://www.news.com.au/technology/in...-1226418741284