Came across this on another forum I frequent, its worth a read and listen, especially if you get bothered with these type of scam calls. I will warn you there is some bad language in the recording.-

Scam Microsoft IT Support call (you have to listen to it!) - CNET Computer help Forums

If you don't want to read it all you can go straight to the recording here-

https://app.box.com/s/0yluyszg1qj2l83ynbm2