Recently my office server/computer was hit by the Cryptolocker ransom ware.
After hiring an IT specialist and messing around with it for 2 days, we just had to give in and pay the $300 to get the files unencrypted.
I hated to send money to the %*#!ers but, it would have exterminated months of work.
(It got through to the backup EHD as well)
Now, I backup to the EHD and then unplug it as soon as it's finished.
If you get rid of the virus that's currently on the computer, it will not decrypt your files and they'll be gone forever.