CHICAGO (CBS) — A computer virus exposed by the FBI last year could affect your access to the Internet starting Monday.

Agents arrested the people behind the virus in 2011. The malware was first detected about five years ago.

So why would this happen?

Well, the FBI set up a temporary fix to allow computer users to still have Internet access while trying to determine if their computer was infected with the so-called “DNS Changer” malware.

That temporary solution expires on Monday. So, if you haven’t checked for the malware yet, your computer may stop working properly.

The FBI has set up a website to help users determine if they still have the DNS Changer malware and what to do to get rid of it. You can click here to access that site.

Federal agents charged a group of people from Estonia and Russia who allegedly created the malware that messes with users’ Internet access.

DNS (Domain Name Service) is the backbone of the Internet that connects a website (cbschicago.com) to a numerical address associated with that site. It’s been likened to a phone book for the web.

The suspects in this case created malware that redirected users to bogus DNS–basically sending people to sites they didn’t search for.

At the time, the FBI set up temporary servers to route the web traffic correctly, while giving computer users time to fix the virus.

The malware is not new, and there is no planned “computer attack” on Monday.

Those FBI servers go off-line on Monday, meaning that if your computer is infected, you won’t have access to the web.

Initially, about a half million computers in the United States were affected. Now, experts estimate that number ranges from about 40,000 to 60,000.

If you do have the malware, you can also contact your Internet service provider.