Bit of a saga I know, but worth noting:
There's a 'thing' going around at the moment where someone (in my case an Asian sounding guy) calls you at home and says he is from 'Windows' and that your computer has been identified as 'running slowly' before offering to 'update and rectify' the problems....
A friend was called three times by this guy and (being a suspicious soul, asked him who he was, who he claimed to represent and what EXACTLY was he offering to do??
His replies were 'considered' and sounded legitimate UNTIL said friend asked "Where did you get my number??"
He replied: "You registered your computer with 'windows' on start-up' and your IP Address was registers automatically with your details, including phone number...."
"Hmmm", said the friend, "the problem I've got with that is that the computer I currently use is being loaned from my mum who doesn't live here, so you wouldn't have MY number, would you....??"
Phone goes dead....
Can't totally say it WAS a 'scam', I'll let you draw your own conclusions but please be wary of anything similar happening to you or yours....