Ransomware is still on the rise. Many haven't heard about this type of malware and aren't aware that they could lose all of their valuable files in one unfortunate incident. It is as simple as opening an email attachment or downloading something from the web that isn't what it seems to be. Once bitten by this kind of malware, the only thing you can do is pay the ransom (and hopefully you will get your files back) or restore your files from a backup.
The one and potentially most important thing that I did not mention in my previous posts about "Keeping your PC Safe" is that regular back-ups are so critically important. And ideally you would have a backup that is not physically in the same location as your PC (i.e. an on-line backup). There are many ways to do this including Microsoft's OneDrive, Google Drive, Carbonite, Crashplan, SpiderOak, etc. See a review here: The Best Online Backup Services of 2017
The steps below are the summary of a previous article and are most important. Please see them in more detail here: Keep Your PC Safe. But if these fail, backup is your only hope against ransomware.
1. Change your DNS settings to use OpenDNS
2. Install either Firefox or Google Chrome and use it instead of Internet Explorer (Edge is ok).
3. Use Windows 10 and it's built-in antivirus software
4. Make sure your software is up-to-date
5. Uninstall Adobe Reader and install Foxit Reader instead.
6. Make your Windows login a "standard" user instead of an administrator.