A call from someone claiming to be Microsoft technical support could be incredibly helpful, or it could ruin your day.

Kennesaw police are warning folks of an uptick in a phone scam involving fake Microsoft staff who are bilking people of money.

Here’s how it works: Someone calls claiming to be with Microsoft, one of its brands or a Microsoft contractor saying they are checking into a computer problem, infection or virus that has been detected.

Then they tell the victim that they will need to pay a service fee to have the nonexistent problems fixed.

They will also often push the customer to buy a one-year computer maintenance subscription.

The cops said scammers often use pay phones, disposable cell phones or stolen cell numbers, which complicates tracking down the perpetrators.

"The callers present themselves in a professional manner and sound genuine," Kennesaw cops said in a Facebook post. "... We strongly advise you simply hang up if they receive a call of this nature and not to respond to any communications from these scammers."

The actual Microsoft company doesn’t cold-call people in regards to infected computers, police said.

Microsoft has some tips online to steer clear of scams.

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Channel 2’s Consumer Advisor Clark Howard explains how you can avoid this issue.