Nightly News | July 08, 2012
>>> back in this country a cyber threat is making a lot of people nervous tonight. the prospect of a nasty computer virus could cut off internet access . we will get more of that story from our justice correspondent pete williams .
>> reporter: a system run by the federal government has helped computers infected with a virus connect to the internet. that fbi run system shuts down midnight sunday for some in the u.s. logging on monday could be a problem. odds are your computer will not be affected but if it is you can blame this man, one of six astone ians charged. affected computers were hijacked into using internet servers that sometimes redirected them to sites the user didn't want. the scammers made money for ads they posted.
>> absolutely brilliant what these guys were doing. they had found a way to tap into one of the most lucrative sources of money on the internet and they have online advertising .
>> reporter: when those behind the scam were arrested affected users were allowed trouble free surfing. the fbi estimates about 45,000 computers in the u.s. are still infected. you can check yours by logging on to this website, dcwg.org. most internet service providers can help, too.
>> the odds aren't very high that you will be infected. if you are infected you probably don't know. and on monday if your internet goes out you are going to have a hard time fixing your computer.
>> reporter: a simple test now to save potential trouble later. pete williams nbc news washington.