I wrote the piece below for another web site in 2012 and this scam is still going on in 2016. To this day I still get calls unsolicited telling me there are errors on my computer which the caller will helpfully cure for me. This is a well known con, they are ringing people at random looking for someone they can rip off.
My answer is to tell them what I think of their morals. Unfortunately others are taken in by these charlatans.
Article from November 2012
I spoke to a couple last week who had received an unsolicited telephone call from someone who gave the impression he was representing Microsoft. Unfortunately they believed him and let him take remote access of their computer. When he had finished remotely fiddling around their computer which had been working perfectly well was left unusable. He even charged them for the work he had done messing up their machine. A while back I had a conversation with another elderly gent who had similarly been taken in by one of these calls. In both of these cases it cost them a considerable amount to get back to a working computer. The couple I mentioned initially,having lost faith in their PC, went out and bought a new one. Now this is a well known scam. I've picked up my phone to people claiming they are from Microsoft (or Windows) and that they have spotted a problem one my computer many times. Now I'm fairly computer literate and I give them short shrift, but to those not so savvy they sound very convincing. These calls are not from Microsoft! Microsoft do not and would not make such calls.