Just taken a 'phone call from someone purporting to be a "Windows Support" person who said I had serious issues with my system. He would not quantify what the problem was verbally, and insisted that I log on to "show me the problems" I tried to determine who he was exactly and who he was working for but all I got were questions to determine who I was and repeated demands to log on. The call was quite demanding and persistent. Is this for real or a scam? Any advice will be appreciated.