That type of ransom ware is a million dollar business worldwide. People are duped all the time into calling and allowing those idiots to enter their computers.
After that they start the ransom exploit of getting you to put in your credit card to pay for the program which will clean the computer. There was never anything in the computer except their very clever software. CCT is right about having a backup. Windows 7, Acronis, TODO, and many others work very well.
But the ransome ware can be removed easily before all that with malwarebytes and if nessecary, Combofix.
Oh and most of these people operate from offshore jumping through a local phone number. Little if anything can be done about it as in the country they work from there are no laws against this.