My favorite on this was when these idiots called my then 90 year old Mother and told her she had a problem with her Windows computer. I got on the phone and told them that she not only didn't have a Windows computer but had never used one in her life and was amazed how a non existent computer could have problems. I told them to stop calling and they never called again.
A friend has a pc and it is not connected to the internet and he has gotten these calls as well.