If your computer gets infected with a Trojan called the "MonaRonaDona virus," be careful with what you use to wipe it off your computer, says antimalware software provider Kaspersky Lab. MonaRonaDona is part of an elaborate scam to sell fake antivirus software, Kaspersky researchers say.

Unlike most viruses and Trojans which try to go about their evil task as invisibly as possible, the MonaDonaRona Trojan displays a broadly visibly message in front of the victim. It says, “Welcome to MonaRonaDona. I am a Virus & I am here to wreck your PC. If you observe strange behaviour with your PC, like program Windows disappearing, etc., it’s me who’s doing this.” The message claims it’s all part of a human rights protest.

But according to Kaspersky Lab researcher Roel Schouwenberg, MonaRonaDona is mainly a way to panic victims, who then may start a Web search to find out more about it, only to find fake online stories and bogus commentary that instruct victims to use fake antivirus tools — the prominent one being called Unigray, available from the Unigray.com Web site, for about $39.00.

“There was a link at Digg and at YouTube promoting it,” says Schouwenberg, who writes about it Monday in a Kaspersky Lab blog posting.

While fake antivirus software scams have cropped up in the past, the MonaRonaDona scam may be unprecedented in terms of its reliance on social engineering in the online world to get victims to download software that removes the MonaRonaDona message but may still be in itself dangerous.

As to how the MonaRonaDona Trojan manages to propagate, Kaspersky Lab sees a link with another piece of “fake” software called RegistryCleaner 2008.

“We’re still researching this but it may be connected with this,” says Schouwenberg, who calls the MonaRonaDona Trojan of the past week to be among the most elaborately orchestrated scams he’s seen.

The bottom line is to clean computers with software from valid antimalware vendors that can detect the bad code, he adds. (Compare Antivirus products.)