I got one too, they CLAIM they are from Windows and that your computer is corrupted. He asked for a "serial number" at least that what I think he said, couldn't really understand him. Informed I wasn't near my computer, so he said he would call back and was persistent on a specific time. Guessing it's a scam.
Just received a call from this number. Claimed he was calling from Windows and that my computer was corrupted. I asked him where he was calling me from and was told Manchester, UK....I live in Ontario, Canada. I told him I thought he was full of poop and he hung up on me.