Police are warning the public about a pervasive computer scam that can ruin victims' credit and cost them thousands of dollars.

"It's horrible. It's one of the worst examples of social engineering I've ever seen," said Paul Profeta of Forest Computers.

Each week numerous people come into Profeta's shop who have fallen victim to the scam, he said.

Scammers call homes claiming to be a representative from Microsoft or another well-known computer company. They claim that they've noticed slowdowns on the household computer and offer to fix it – if computer owners give them remote access to their computers.

"That's like you going and opening the door to a guy who wants to steal everything from your home. You wouldn't do that, right? So don't do that to your computer because it's exactly the same thing," said Det. Julius Kovacs of the Winnipeg police's commercial crime unit.

Giving the fake representative remote access means they have access to all of the personal information on the computer, including online banking information.

"Usually once a system makes it [to the shop] it has been compromised, and people are in trouble with their banks and credit cards," said Profeta.

The Canadian Anti-Fraud Centre said 80 per cent of the complaints it receives are about the computer virus scam.

"It can ruin your entire identity, and it can cost a lot of money to restore your identity back to where it was," Kovacs said.

If you have been contacted by a scammer, Kovacs recommends hanging up immediately and calling a credit monitoring company and adding your name to a fraud watch list just in case.

And if you've given the scammers access, Profeta recommends bringing your computer to a professional right away. For about $100 your computer will be scanned and cleaned of any spyware installed by the scammers.

More information on this scam and others is available at the Canadian Anti-Fraud Centre website.

-- with a report from CTV's Stacey Ashley