What to do?
Dave LeClair, at MakeUseOf, has a very interesting infographic showing the history, how it can happen, and what you can do if you should happen to get infected.
The first commenter reiterates an important point brought up at a recent general meeting: don’t be using your computer day-to-day logged in as an administrator!
PYBT for the whole shebang: Ransomware Keeps Growing – How Can You Protect Yourself?
Graphic from the article