Ron,
I received this same call today. I was very suspicious and asked for his ID and phone number. He asked me to get a pen and paper and he gave me a bunch of letters and numbers. The thing is he ALREADY had my CLSID key when I typed in assoc, he asked if it matched or not.
I said yes, almost ( I lied) then another guy gets on wants me to do another Ctrl -r and I said no way and hung up.
My question is, what now? They already had my CLSID number.
Someone called from this number and tried to tell me there was a problem with my computer and he was calling to help me fix it. My computer was fine, but he kept insisting so I hung up on him.
A gentleman with a heavy accent called me to tell me my computer was automatically downloading infected files. Said he was calling from Microsoft service center. I was not on my computer at the time could not get to my computer so I hung up on him.