According to The Press-News, PC users are encouraged by the FBI to visit a website run by its security partner,

A test will inform you if you are infected and explain how to fix the problem. Infected users will not be able to connect to the Internet after July 9.

Most victims don't even know their computers have been infected, although the malicious software probably has slowed their web surfing and disabled their antivirus software, making their machines more vulnerable to other problems.

Last November, the FBI and other authorities were preparing to take down a hacker ring that had been running an Internet ad scam on a massive network of infected computers.

"We started to realize that we might have a little bit of a problem on our hands because … if we just pulled the plug on their criminal infrastructure and threw everybody in jail, the victims of this were going to be without Internet service," said Tom Grasso, an FBI supervisory special agent. "The average user would open up Internet Explorer and get 'page not found' and think the Internet is broken."

Visit this website run by the FBI's security partner, to test your computer and to fix the problem.

You may download additional information from the FBI website about how to fix your computer if it is infected.