Hundreds of thousands of people could lose Internet service on Monday when the FBI shuts down servers from an online fraud ring that allegedly planted a virus among computer users.

The FBI says about 252,000 computers worldwide could be affected and that about 45,000 of those computers are in the United States.

Users can check whether their computer is infected with the malicious software — often called malware — by visiting, a site run in cooperation with the FBI, or by visiting an anti-virus site such as McAfee.