Jerome Dorfman relies heavily on his computer for his law practice. He considers himself tech-savvy. That is why he was concerned about a phone call 10 days ago claiming to be from tech support.

"He said he was from Microsoft, and I had downloaded a corrupt file," Dorfman said.

Not having any issues with his computer, Dorfman immediately suspected a problem.

"And I said 'Well, obviously you know who I am, you know my email address, send me an email,'" Dorfman said. "[At that point,] he hung up."

Dorfman is not the only one to get a call.

Bill Efron is the northeast regional director for the Federal Trade Commission. He says tens of thousands of consumers are being targeted.

"You'll get a call from someone claiming to be a computer tech service person affiliated with a legitimate computer company like Microsoft, Dell, MacAfee or Norton. They'll tell you that your computer is infected with viruses or other malware and what they are trying to do is trick you into buying software that you don't need."

How big is the scam? The FTC claims consumers have already lost tens of millions of dollars.

"Do not give your password out over the phone," Efron said. "Legitimate companies do not call and ask you for your password. Do not give someone access remotely to someone if they call out of the blue. Never rely on caller ID to confirm that a caller is legitimate."

Just last October, the FTC took action against six companies that they claim were scamming consumers. Again, it all started with a cold call asking if you have any computer issues.

"If someone calls you and tells you that your computer has a problem, the best thing to do is hang up the phone," Efron said.

"People, especially the elderly, tend to fall for these kind of scams because they're a little more trusting, and a little less technically savvy," Dorfman said.