These ransomware virus's are a pita for me. I'm an IT engineer.
They have made a massive comeback in the last 2 months and are arriving via e-mail or being downloaded.
Disguised as a pdf file the file extension is actually .exe
I would suggest as no anti virus can actually detect them as of yet and when they do a new version is released which can't be detected, to enable file extensions so you can see just what you're clicking onto and pay attention to what you're clicking as they load in the background and do there stuff without you knowing.
If it gets hold of your system then they can encrypt pictures, pdfs, docs, excel files each with a separate algorithm meaning unless you have the key (different for each file) which is individually stored on the bad persons computer - You're attached to another object by an inclined plane, wrapped helically around an axis.
Be wary everyone