RansomWare-This type of virus is one that is typically distributed through a fake email claiming to have a greeting, card, invoice, check, PO, or something of the sort attached. It can also be published as a fake adobe or java update. In case you aren’t familiar with the utter destruction, you should read here http://www.bleepingcomputer.com/news/security/the-locky-ransomware-encrypts-local-files-and-unmapped-network-shares/
Basically if you don’t have backup, you have likely lost all of your files. In some iterations it is even smart enough to remove previous versions saved by Windows using VSS so that you can’t simply restore them to yesterday. In 95% of cases, you better have a good backup, I prefer Crashplan, I feel like it is the best backup solution on the market and is very very inexpensive. I have it on every device I own.