Other preventive measures are being mentioned here:
http://www.pcadvisor.co.uk/features/security/3491195/how-protect-yourself-from-cryptolocker-attack/
These measures consist of making back-ups and save these offline. Make online back-ups through free services.
The most important message however is to never to open a file or link from an email or on a social site
if one does not know whether it was sent deliberately for recipient.
Use this little program to prevent: http://www.foolishit.com/vb6-projects/cryptoprevent/
CryptoPrevent is completely FREE for personal and commercial usage!
greets,
polonus