There seems to have been an increase in the “PC error scam” where someone will call you, say they are calling from “Windows Security Systems” or a similar name to make you think that it is an official call from Microsoft, telling you that your computer is sending error reports. All these people want is your money (and possibly remote access to your PC).
So, remember, Microsoft never call clients. You most like do not have any problem with your computer. These people are con artists and just want your money. For a full explanation of how the scam works, read the Webologist’s guide to PC Support Security Scams – ZFSENDTOTARGET CLSID Trick