The Associated Press (via BlueRidgeNow.com) reports:
... tens of thousands of Americans may still lose their Internet service Monday [July 9] unless they do a quick check of their computers for malware that could have taken over their machines more than a year ago.

Despite repeated alerts, the number of computers that probably are infected is more than 277,000 worldwide, down from about 360,000 in April. Of those still infected, the FBI believes that about 64,000 are in the United States.

Users whose computers are still infected Monday will lose their ability to go online, and they will have to call their service providers for help deleting the malware and reconnecting to the Internet. ...

The problem began when international hackers ran an online advertising scam to take control of more than 570,000 infected computers around the world.
... To check whether a computer is infected, users can visit a website run by the group brought in by the FBI: http://www.dcwg.org .