please see my blog
http://thesuperkev.blogspot.com.au/2012/09/scam-alert-scam-alert.html
this co called IT Support company Quantumpcsupport.com they are scammers, they get you to look at genuine errors on your computer, then they tell you that these errors are being sent to their servers and they will remove them for a fee, easiest way to get these to stop calling is to tell them that you are a IT Administrator and you know that they are trying to scam you they will soon hang up and put you on the list of numbers not to ring.