I've found easiest way yet to stop these scammers before they get to their sales pitch. Man with heavy accent says "Hello,this is Michael" to which I answer "you have wrong number;no Michael here";after a couple back and forth with him insisting HIS name is Michael, I say no never Michael lives here he hangs up. Next day, same voice,this time says he's "Mark". I do same thing insisting no,no,never no Mark living here. Last time he said "Oh my God "and hung up.
Received the same type of call, except caller Mike (heavy Indian accent) identified himself as being from Microsoft Tech Support and that one of my Windows computers has a Trojan horse and has stopped responding to Windows updates and that they needed to fix it. When I said that I was running MAC OS (which I don't), he hung up. Suspect that this scam is attempting to gain access to files and P/Ws by getting you to allow them remote access.
This person called at 9:32 am April 15, 2015 with a heavy Indian accent mentioning about Windows update, "I shouted who are you?". He got scared and he hung up. Haha. Scammer. This guy if from India and spoofing someone's caller ID's number. I added the number to my blocked number reject list.