Hopefully you've never seen this.
This nasty little infection encrypt all your files, and forces you to pay to have them unlocked again.
This does not only encrypt files on your computer, but also anything with a drive letter USB, camera cards, and mapped network locations.
Office documents open like gibberish, and some files will not open at all. This is why it is always a good idea to backup anything you cannot live without in another location not attached to your computer.
Burn documents and pictures to CD or DVD, transfer to the cloud, Facebook, or external hard drive that you disconnect/shut off when you are not backing it up.
This infection usually comes in from ads online, email attachments from friends/unknown sources "claiming to be account statement or report".
This is a warning of what is out there and why it is important to keep things backed up. Your computer can be cleaned, but most times your data is not so lucky.