Beware of false PC issues Scam
 

BBC News - Warning over anti-virus cold calls to UK internet users

Had this happen with a program called Ultra Defrag telling me everything was infected and hard disk failing then when clicked to run it amazingly wanted by credit card.

Luckily on other laptop I googled it and renewed my Norton killer which I had let lapse months ago, the Ultra malware still kept shutting down as clearly didn't wish Norton to get it. However after half a dozen restarts Norton wiped it out.

Not sure where it got downloaded from initially which is a concern.