Fake Microsoft tech support. As stated above they are claiming that your computer security is at risk, and offering pricey "computer fixing" services. The whole thing is a scam.
They acting like they were from Microsoft and that my computer was sending out signals that would harm my computer and that it was in the back of my computer. I asked if they could tell me more about what it was called so I could look it up on the web and they said they would call me back and asked when a good time to call was.