An internet blackout is looming for thousands of computers infected with the doomsday virus. Apparently this virus routed computers' searches through a particular DNS and earned millions in bogus advertising revenue for the creators of the virus. Once the scam was busted, the FBI set up a server for infected computers to go to. But the FBI server will shut down Monday, so infected computers will experience a blackout.
The best way to check if your computer is infected is http://dns-ok.us/
A "clean" computer will look like this: