We have seen a re-emergence of this nasty Ransomware of late. For those of you that are unaware, its’s an email-delivered file that once run, encrypts the documents on your PC (or any mapped network drive). The author will then ask for payment to unlock the files.
Please be on the look out for emails with .ZIP attachments.. Be warned once the files are encrypted they cannot be recovered. They have to be restored from a backup. If you feel you have no choice but to pay the ransom, (have in mind this is extortion) please use a pre-paid card and not your credit or debit card.
The Crypto locker virus (actually it's a program) is very difficult to stop. 
So please be very aware of emails from senders you don’t know.
Also disabling hidden file extensions in Windows may help you pick up the virus before it gets installed. Make sure your backups are good, if you get this virus you’re going to need them!!