Kenny (with very heavy Pakistani accent) from Microsoft Technical claimed my computer was sending spam with viruses...., funny thing, they "knew" it was me, but didn't know my name, they "knew" it was my computer, but they didn't "know" what the computer IP address was.
If you go ahead with the ruse, they eventually ask you to open a TeamViewer or other remote session to give them full access to your computer. They can then copy any of your personal data, and install programs to allow other hackers to do damage.